IRLF 


nioemttj  of  d 
4  4 (California 


THE   FUELS 
OF   THE   HOUSEHOLD 

Their  Origin 
Composition  and  Uses 


By  MARIAN    WHITE 

TEACHER    OF    DOMESTIC   SCIENCE 

McKlNLEY    MANUAL   TRAINING    SCHOOL 

WASHINGTON,  D.  C. 


WHITCOMB   &   BARROWS 

BOSTON    1909 


\N  5 


COPYRIGHT  1909  BY 
MARIAN    WHITE 


THOMAS  TODD  CO. 

PRINTERS 
14  BEACON  ST.,  BOSTON,  MASS. 


TO   MY   FATHER 


190898 


PREFATORY   NOTE 

TN  writing  this  essay  I  have  assumed  an  audience  of 
•*•  young  housekeepers  and  those  who  are  to  become 
such.  I  have  sought  the  best  information  on  the  subject 
which  the  abundant  professional  and  bibliographical  re- 
sources of  the  National  Capitol  afford,  but  I  have  thought 
it  best  to  use  a  style  of  direct  statement  rather  than  one 
embracing  complex  statistical  forms. 

I  am  especially  indebted  to  my  father,  Dr.  Charles  A. 
White,  whose  abundant  published  writings  on  geological 
and  botanical  subjects  are  well  known.  He  has  not  only 
placed  his  large  accumulation  of  manuscripts  at  my  dis- 
posal, but  I  have  constantly  had  the  benefit  of  his  counsel 
and  of  his  personal  recollections  of  many  of  the  con- 
ditions and  events  of  which  I  have  written.  M.  w. 


CONTENTS 

PAGE 

I.    INTRODUCTION  .                i 

II.     COMPOSITION  OF  FUELS 5 

III.  COMBUSTION,  IGNITION,  AND  INCANDESCENCE       .        .  10 

IV.  THE  SOLID  FUELS:  MINERAL  COAL,  COKE,  AND  PEAT,  26 
V.    THE  SOLID  FUELS:  WOOD  AND  CHARCOAL  .*               -37 

VI.     THE  SEMI-SOLID  FUELS 51 

VII.    THE  LIQUID  FUELS 60 

VIII.    GASEOUS  FUELS         .        . 73 

IX.    ECONOMY  OF  FUELS 81 

X.    ELECTRICITY 93 

INDEX 96 


vii 


''  V  £  &  S  |  T  Y 


CHAPTER    I 
INTRODUCTION 

THAT  the  natural  resources  of  light  and  heat  are 
universal  is  shown  by  the  energy  and  diffusion 
of  the  sun's  rays  throughout  the  solar  system,  by  the 
intensity  of  heat  in  active  volcanoes,  and  by  the  fierce- 
ness of  lightning  flashes  when  storms  prevail.  So  small, 
however,  is  the  draft  that  man  has  hitherto  been  able 
to  make  upon  those  great  natural  resources  for  economic 
uses  that  nearly  all  his  supplies  for  those  uses  are  obtained 
by  artificial  means. 

To  a  comparatively  small  extent  the  sun's  rays  have 
been  utilized,  and  under  specially  favorable  conditions 
light  is  now  abundantly  produced  by  the  artificial  con- 
trol of  electric  currents,  and  heat  for  domestic  and  other 
economic  uses  is  largely  obtained  by  the  same  means. 
The  fact  still  remains  that,  with  exceptions  to  be  men- 
tioned on  following  pages,  the  light  and  heat  which  are 
practically  used  in  the  household  and  industrial  arts  are 
artificially  produced  from  substances  called  fuels,  by 
chemical  processes  which  are  ordinarily  called  combustion 
and  incandescence,  respectively. 

The  same  kinds  of  fuels  are  used,  or  are  usable,  in 
the  household  that  are  used  in  the  industrial  arts ;  and 
although  much  the  greater  part  of  the  fuels  which  are 
now  utilized  by  man  are  consumed  in  the  world's  great 
activities,  success  in  housekeeping  is  quite  as  dependent 

i 


2  HOUSEHOLD    FUELS 

on  the  skillful  selection  and  management  of  fuels  as  it 
is  in  the  case  of  great  industrial  enterprises. 

The  three  principal  objects  for  which  our  household 
fuels  are  used  are  the  warming  of  our  dwellings,  the 
lighting  of  them,  and  the  cooking  of  our  food.  Although 
it  is  true  that  light  may  be  produced  with  little  or  no 
accompanying  heat,  and  that  heat  may  be  produced  with 
little  or  no  light,  all  the  fuels  which  are  now  used  for 
lighting  may  be,  and  in  many  cases  are,  used  for  heating. 
Therefore  the  term  "fuel"  is  employed  to  designate  all 
those  combustible  substances  which  are  used  in  our 
households  and  in  the  industrial  arts  to  produce  either 
light  or  heat,  or  both.  The  fuel  substances  which  are 
to  be  considered  in  the  following  chapters  are  such  as 
are  commonly  used  in  the  household,  and  all  of  them 
are  obtainable  in  the  fuel  markets  or  from  special 
dealers. 

For  convenience  of  reference  on  following  pages, 
household  fuels  are  divided  into  solid,  semi-solid,  liquid, 
and  gaseous  fuels.  The  solid  fuels  are  mineral  coals 
and  coke,  wood  and  charcoal,  and  peat.  The  semi-solid 
fuels  are  wax,  fats,  resin,  stearin,  palmitin,  spermaceti, 
and  paraffin.  The  liquid  fuels  are  the  oils  and  alcohols. 
The  gaseous  fuels  are  the  natural  and  artificial  gases 
which  are  readily  combustible,  but  which  are  not  con- 
densible  to  a  liquid  condition  except  at  extremely  low 
temperatures,  too  low  for  practical  consideration.  Fuels 
are  also  in  part  grouped  with  reference  to  their  origin ; 
as  some  are  of  animal  origin,  some  of  vegetable  origin, 
and  some  are  derived  directly  from  the  earth.  The  last 
mentioned  fuels  are  appropriately  called  mineral  fuels, 


HOUSEHOLD    FUELS  3 

although  some,  if  not  all  of  them,  are  primarily  of 
vegetable  origin. 

In  discussing  these  fuels  and  their  uses  on  following 
pages,  the  mental  scene  of  all  the  processes  and  utilities 
which  are  mentioned  is  the  household.  The  households 
of  our  country  are  so  distinctively  American  that  the 
subject  of  this  essay  is  naturally  devoted  to  that  type. 
The  historical  range  of  that  type  is  short,  because  the 
political  history  in  connection  with  which  it  was  devel- 
oped is  short  compared  with  that  of  other  countries. 
And  yet,  eventful  as  that  short  political  history  has  been, 
the  household  affairs  which  have  pertained  to  the  use  of 
fuels  have  been  quite  as  eventful. 

For  example,  there  are  aged  persons  now  living  who 
were  born  and  reared,  not  upon  the  westward  moving 
frontier,  but  among  the  settled  population  of  the  Eastern 
states,  who,  during  their  childhood  and  early  youth, 
never  ate  any  food  that  was  not  cooked  either  at  the 
open  kitchen  fire  or  in  the  adjacent  brick  oven.  No  cast- 
iron  ranges,  nor  even  the  commonest  cook  stoves,  had 
then  come  into  use.  Neglected  fires  were  rekindled  by 
means  of  the  flint  and  steel,  or,  if  the  tinder  box  was 
out  of  order,  one  of  the  children  was  sent  to  a  neighbor's 
house  to  " borrow  fire."  A  half-burnt  brand  was  taken 
from  the  kitchen  hearth  and  swung  over  the  head  of  the 
running  child  to  keep  it  burning.  Friction  matches  were 
not  then  invented.  The  usual  household  light  was  that 
of  rude  tallow  candles,  and  the  best  light  then  available 
for  household  use  was  obtained  from  whale  oil. 

This  oil  deserves  special  mention  because  the  demand 
was  then  so  great  that  ships  sailed  every  sea  to  obtain 


4  HOUSEHOLD    FUELS 

it.  Mineral  oil,  except  in  quantities  too  small  for  prac- 
tical use,  was  not  then  known  to  exist  in  our  country. 
When  that  oil  was  discovered  by  deep  boring,  it  came  in 
such  quantity,  and  its  refined  product,  kerosene,  came 
so  suddenly  and  abundantly  into  use,  that  the  whaling 
business  was  destroyed,  and  the  ships  returned  to  port 
empty  and  rotted  at  their  docks.  Illuminating  gas  from 
coal  had  hardly  passed  its  experimental  stage,  even  in 
the  larger  cities,  and  the  most  prophetic  mind  among  the 
people  never  conceived  of  lights  so  brilliant  and  service- 
able as  those  with  which  our  households  and  public 
buildings  are  now  furnished.  Churches  and  public  halls 
were  not  warmed,  and  in  bitter  winter  weather  the  whole 
family  gathered  around  the  roaring  wood  fire  upon  the 
great  kitchen  hearth.  No  system  of  general  housewarm- 
ing  was  then  known,  and  mineral  coal  was  seldom  seen 
except  upon  the  blacksmith's  forge.  That  such  revolu- 
tions as  these  could  have  occurred  with  relation  to  the 
domestic  customs  of  a  progressive  people  within  the 
memory  of  an  individual  is  marvelous  but  true,  and 
the  half  has  not  been  told. 


CHAPTER    II 
COMPOSITION    OF    FUELS 

T)ECAUSE  the  foregoing  classification,  or  manner  of 
-*-*  grouping,  of  the  fuels  is  followed  in  the  subsequent 
chapters,  it  will  be  necessary  to  remember  them  to  have 
a  clear  understanding  of  the  statements  therein  made. 
It  is  also  quite  necessary  for  one  who  desires  to  know 
fuels  to  become  familiar  with  the  elementary  facts  per- 
taining to  their  composition  and  their  manner  of  com- 
bustion to  produce  heat  and  light.  It  is  for  the  purpose 
of  briefly  summarizing  those  facts  that  this  and  the  next 
following  chapters  are  introduced. 

The  Chemical  Elements.  Not  only  the  earth  and 
all  that  pertains  to  it,  including  its  solid  mass  as  a  planet, 
but  its  waters  and  all  that  they  contain,  its  atmosphere 
and  all  that  pervades  it,  and  all  the  animal  and  vegetable 
forms  which  dwell  or  grow  upon  it,  consist  of  various 
kinds  of  matter  which  are  called  elements  and  com- 
pounds of  elements.  Those  chemical  elements  have  never 
been  divided  into  other  substances,  as  the  compounds 
have  been,  and  they  are  generally  regarded  as  incapable 
of  such  division.  Their  number  at  present  known  is 
above  seventy.  In  density  and  other  properties  they  vary 
from  ponderous  metals,  as  iron,  on  the  one  hand,  to  in- 
visible gases,  some  of  which  are  lighter  than  air,  on  the 
other.  Very  few  elements  are  found  free  in  nature,  but 
are  usually  combined  with  other  elements.  Every  such 

5 


'      Of    THt 

UNIVERSITY 


0  HOUSEHOLD    FUELS 

combination  produces  a  substance  which  is  quite  unlike 
any  of  the  elements  of  wh^ch  it  is  composed. 

Chemical  Reaction.  The  inclination  which  the 
elements  have  to  unite  to  form  compounds  whenever 
they  are  brought  into  intimate  contact  under  such  con- 
ditions as  solution  and  heat  varies  so  greatly  that  an 
element  will  often  leave  its  associate  in  a  compound  and 
unite  with  another  element.  The  two  freed  elements 
either  unite  to  form  another  compound,  or,  in  passing 
off,  each  unites  with  other  elements.  This  exchange  of 
association  is  called  chemical  reaction,  and  all  known  sub- 
stances are  liable  to  be  affected  by  such  reaction.  What- 
ever may  be  the  result  of  such  questions  as  have  lately 
been  raised  as  to  the  destructibility  or  transmutability  of 
elements,  such  possibilities  need  not  be  considered  with 
relation  to  the  elements  concerned  in  fuel  combustion. 
We  see  and  handle  those  elements  in  their  visible  and 
tangible  condition,  and,  although  they  become  invisible 
and  intangible  when  their  combustion  has  occurred,  we 
demonstrate  that  they  still  exist  when  we  account  for  the 
products  of  combustion. 

Sometimes  chemical  reaction  is  slow,  as  in  the  rusting 
of  iron  and  in  what  is  ordinarily  called  decay  of  animal 
and  vegetable  substances.  Sometimes  it  is  very  rapid,  as 
in  the  burning  of  fuels,  especially  the  fierce  flames  of 
liquid  and  gaseous  fuels.  Sometimes  it  is  explosive, 
as  is  seen  in  the  so-called  fire  tests  of  the  mineral  oils, 
and  by  the  disastrous  results  of  the  careless  handling  of 
gasoline. 

The  Fuel  Elements.  There  are  only  a  few  of  the 
large  number  of  the  chemical  elements  with  which  we 


HOUSEHOLD    FUELS  7 

shall  have  anything  to  do  in  the  study  of  household  fuels. 
Indeed,  there  are  only  three  of  them  which  take  really 
an  active  part  in  the  combustion  of  fuels,  namely,  carbon, 
hydrogen,  and  oxygen ;  but  it  will  be  necessary  to  men- 
tion a  few  others  as  accessories  to  combustion  and  to 
ignition,  or  the  kindling  of  fires.  Each  of  the  elements 
generally  assumes  a  very  different  condition  in  every 
combination  which  it  makes  with  another  element,  but 
such  trans  formations  need  be  mentioned  only  for  those 
which  are  immediately  concerned  in  fuel  combustion. 
For  example,  oxygen,  which  is  so  abundant  that  it  is 
estimated  to  constitute  nearly  one-half  of  the  bulk  of  the 
earth,  exists  in  a  great  variety  of  conditions.  It  enters 
largely  into  the  composition  of  minerals  and  into  the 
solid  part  of  vegetable  matter,  where  it  is  necessarily 
solid.  It  is  a  large  constituent  of  water,  where  it  is  of 
course  liquid.  It  constitutes  a  large  part  of  the  atmos- 
phere, where  it  is  closely  associated  with,  but  not  chem- 
ically united  to,  nitrogen.  In  that  association  it  is 
necessarily  gaseous,  as  it  always  is  in  its  pure  state. 

The  diamond  is  the  purest  form  of  carbon  known, 
and  in  that  condition  it  is  one  of  the  hardest  of  known 
substances.  Charcoal,  coke,  and  anthracite,  although 
widely  different  from  the  diamond,  are  nearly  pure  forms 
of  carbon.  All  the  other  solid  fuels,  as  well  as  the  semi- 
solid  fuels,  are  largely  composed  of  carbon,  and  in  these 
fuels  it  exists  in  a  more  or  less  solid  condition.  Carbon 
also  forms  a  component  part  of  all  alcohols  and  oils,  in 
both  of  which  kinds  of  fuel  it  is  necessarily  liquid.  It 
is  an  essential  component  of  all  the  gaseous  fuels,  and 
in  them  it  is  necessarily  gaseous. 


HOUSEHOLD    FUELS 

Hydrogen  in  a  free  state  is  an  inflammable  gas,  which 
burns  with  a  bluish  flame,  and  is  the  lightest  substance 
known.  In  the  gaseous  fuels  it  combines  with  carbon 
and  still  retains  its  gaseous  condition.  In  combination 
with  oxygen,  hydrogen  generally  assumes  the  liquid 
condition,  that  combination  forming  water.  In  all  the 
other  liquid  fuels  of  which  hydrogen  forms  a  part,  it  is 
necessarily  liquid.  Hydrogen  enters  into  the  composition 
of  all  the  solid  and  semi-solid  fuels,  with  the  excep- 
tion of  pure  anthracite,  coke,  and  charcoal.  In  these 
fuels  it  is  necessarily  in  a  correspondingly  solid  condition. 

Accessory  Fuel  Elements.  It  is  desirable  to  men- 
tion a  few  other  elements  which  enable  us  to  get  a  more 
complete  view  of  the  nature  of  combustion.  Nitrogen 
should  be  specially  mentioned  in  this  connection,  although 
it  is  wholly  inert  in  the  process  of  fuel  combustion.  It 
is  very  abundant  everywhere,  associated  with  oxygen 
in  the  atmosphere,  and  when  freed  from  that  association 
by  fire  it  accompanies  the  products  of  combustion  and 
goes  unchanged  to  take  its  former  place  in  the  atmos- 
phere. In  its  pure  state  nitrogen  is  a  colorless  gas,  but 
like  other  gaseous  elements  it  becomes  a  solid  by  some 
of  the  combinations  which  it  makes  with  .other  elements. 
Such  an  example  is  seen  in  the  well-known  saltpeter,  or 
nitrate  of  potash,  which  is  mentioned  among  the  kindling 
materials  in  a  following  chapter  because  it  is  combustible, 
although  not  a  fuel. 

It  is  proper  to  mention  here  that  within  a  few  years 
three  other  gaseous  elements  have  been  discovered  in 
the  atmosphere.  They  are  rare,  or  little  known,  but  in 
fuel  combustion  they  seem  to  hold  the  same  position  with 


HOUSEHOLD    FUELS  9 

relation  to  the  fuel  elements  that  nitrogen  does,  that  is, 
entire  inertness.  The  names  which  have  been  given  to 
these  elements  are  argon,  helium,  and  neon,  respectively. 
The  Importance  of  Carbon  and  Hydrogen.  In 
the  next  chapter  statements  are  made  concerning  the 
process  of  combustion  of  the  different  kinds  of  fuel  which 
show  the  great  importance  of  oxygen  in  all  those  proc- 
esses ;  and  yet  they  show  that  oxygen  is  not  itself  a  fuel. 
The  only  true  fuel  elements  arc  hydrogen  and  carbon; 
but  there  can  be  no  combustion  of  those  elements  with- 
out oxygen.  Being  indispensable,  it  is  fortunate  that 
oxygen  is  always  and  everywhere  at  hand,  free  of  expense 
and  requiring  no  labor  for  its  preparation  and  storage. 
On  the  other  hand,  hydrogen  and  carbon  must  be  obtained 
by  great  labor  and  at  great  expense. 


CHAPTER    III 

COMBUSTION,   IGNITION    AND 
INCANDESCENCE 

OXIDATION.  Oxygen,  which  is  ever  present  in 
the  atmosphere,  has  a  constant  tendency  to  unite 
chemically  with  most  of  the  other  elements.  Consequently 
it  readily  leaves  its  associate,  nitrogen,  to  unite  with 
them,  that  being  the  act  of  oxidation  which  is  to  be  so 
often  mentioned  in  the  following  remarks.  Fuels  ex- 
posed to  the  air  are  all  attacked  by  oxygen  and  undergo 
a  very  slow  process  of  oxidation  at  ordinary  tempera- 
tures, and  without  fire.  This  open-air  oxidation  is  hardly 
perceptible,  even  after  long  exposure,  in  the  case  of  the 
hardest  of  the  solid  fuels,  but  it  always  exists,  and  differs 
from  burning  by  fire  only  in  the  length  of  time  in  which 
it  is  accomplished.  Even  the  amount  of  heat  which  is 
given  off  in  the  process  is  the  same  in  both  cases,  because, 
as  is  well  known  to  chemists,  the  amount  of  heat  which 
is  given  off  by  oxidation  is  always  in  proportion  to  the 
extent  of  that  process.  In  the  case  of  open-air  oxidation 
of  fuels,  heat  is  given  off  too  slowly  to  be  perceptible 
to  the  senses,  but  so  rapidly  in  the  case  of  their  ignition 
that  combustion  results. 

Combustion.  If  fuels  are  placed  in  suitable  recep- 
tacles and  fire  is  applied  to  them,  they  also  take  fire  and 
are  more  or  less  quickly  consumed.  This  process  is  com- 
bustion, the  well-known  burning  of  fuel,  in  which,  instead 

10 


HOUSEHOLD    FUELS  II 

of  the  exceedingly  slow  rate  of  open-air  oxidation,  there 
is  a  violent  and  rapid  oxidation  which  quickly  converts 
the  fuel  into  what  are  called  the  products  of  combustion. 

With  the  exception  of  anthracite,  coke,  and  charcoal, 
all  solid  fuels  contain  enough  hydrogen  to  give  off  more 
or  less  flame.  When  either  of  those  three  fuels  burn, 
there  is  only  carbon  combustion,  and  the  fire  consists  of 
a  bed  of  embers.  Hydrogen  is  often  called  the  greedy 
element  because  it  will  unite  with  oxygen  more  readily 
than  any  of  the  others ;  so  when  hydrogen  is  contained 
in  any  of  the  solid  fuels  it  is  more  readily  ignited  than 
is  the  carbon.  After  the  burning  of  the  hydrogen  has 
ceased,  the  carbon  combustion  proceeds  alone,  forming, 
as  in  the  other  case,  a  bed  of  embers  which,  when  ex- 
hausted, leave  only  the  ashes.  The  manner  of  combustion 
of  the  flame  fuels  will  be  discussed  further  on. 

Products  of  Combustion.  The  products  of  com- 
bustion are,  properly  speaking,  only  those  invisible  gases 
and  vapors  which  pass  off  in  the  upward  current  that  heat 
causes  to  rise  from  the  burning  fuel.  That  term  does 
not  include  smoke,  soot,  or  ashes,  but  they  ought  to  be 
briefly  referred  to  in  this  connection. 

Smoke  consists  largely  of  finely  divided  carbon  which 
has  been  partially  oxidized  in  the  fire  but  not  consumed, 
and,  in  company  with  more  or  less  watery  vapor,  escapes 
from  the  fire  by  the  upward  draft.  Smoke  represents 
wasted  fuel ;  the  denser  the  smoke  the  more  fuel  is  wasted. 
The  very  light-colored  smoke  which  one  often  sees 
escaping  from  chimneys  consists  largely  of  watery  vapor. 

In  the  burning  of  wood  and  some  of  the  softer  coals, 
a  part  of  the  oily  compounds  which  are  included  with 


12  HOUSEHOLD    FUELS 

the  hydrocarbons  are  volatilized,  escape  full  oxidation, 
combine  with  fine,  escaping  particles  of  free  carbon, 
adhere  to  the  inner  walls  of  the  chimney  flue,  and  con- 
stitute chimney  soot.  The  soot  from  wood  fires  is  also 
impregnated  with  creosote. 

Wood  ashes  consist  of  certain  mineral  substances 
which  the  growing  tree  takes  from  the  earth  dissolved 
in  its  food-sap,  together  with  such  accidental  impurities 
as  become  embodied  in,  or  mingled  with,  them  during  the 
growth  of  the  tree,  or  afterward.  Coal  and  peat  ashes 
often  contain  mineral  materials  which  have  accumulated 
while  those  fuels  were  forming.  Certain  of  the  mineral 
substances  which  are  contained  in  the  coal  ashes  are  often 
fused  by  the  fire  into  lumps  which  become  hard  on  cool- 
ing, and  are  commonly  called  clinkers.  Excess  of  ashes, 
and  especially  of  clinkers,  which  sometimes  occurs  in  coal 
ashes,  retards  combustion  by  obstructing  the  under  draft. 
Hard  wood  ashes  contain  much  potash,  which  was  for- 
merly the  chief  reliance  for  making  the  family  soap. 
Ashes  of  the  pines  and  of  the  other  conifers  contain  very 
little  potash,  and  coal  ashes  contain  no  appreciable  amount 
of  it. 

The  chief  products  of  combustion  proper  are  carbon 
dioxide  and  carbon  monoxide,  and,  when  the  fuel  con- 
tains hydrogen,  water  is  produced  as  steam.  It  should 
be  remembered  that  steam  is  invisible.  What  we  gener- 
ally call  steam  is  really  watery  vapor,  or  steam  in  the 
process  of  condensation.  The  two  products  first  named 
originate  in  fuel  combustion  as  invisible  gaseous  com- 
pounds that  are  formed  by  the  chemical  union  of  oxygen 
from  the  air  and  the  carbon  of  the  fuel.  When  two 


HOUSEHOLD    FUELS  13 

parts  of  oxygen  unite  with  one  part  of  carbon,  the  gas, 
carbon  dioxide,  is  formed.  This  gas  is  heavier  than  air 
at  ordinary  temperatures,  but,  heated  by  the  fire  in  which 
it  originates,  its  relative  weight  is  decreased  and  it  rapidly 
rises  with  the  upward  current,  which  also 'mechanically 
assists  it  to  rise.  Carbon  dioxide  is  not  only  incom- 
bustible, but  it  will  extinguish  fire  as  quickly  as  will  water 
if  allowed  to  cover  it.  The  union  of  one  part  of  carbon 
with  one  part  of  oxygen  produces  the  gas,  carbon  mo- 
noxide, which  is  often  seen  burning  with  a  slight  bluish 
flame  over  smoldering  fires  of  both  coal  and  wood.  It 
is  a  product  of  incomplete  combustion,  while  carbon  diox- 
ide is  a  product  of  complete  combustion,  the  carbon  in 
the  latter  case  having  united  with  all  the  oxygen  of  which 
it  is  capable.  Both  of  these  gases,  particularly  the  carbon 
monoxide,  are  fatally  poisonous  if  freely  inhaled. 

Water  has  been  proved  to  exist  in  the  products  of 
combustion  of  certain  fuels  which,  before  their  combus- 
tion, were  known  to  contain  neither  oxygen  nor  water, 
but  to  contain  hydrogen.  This  water,  therefore,  must  have 
been  specially  formed  during  the  combustion  by  oxygen 
from  the  air  uniting  with  hydrogen  of  the  fuel.  Such 
water  passes  off  in  the  form  of  steam,  and  finally  as 
vapor,  together  with  other  vapors,  accessories,  and 
products  of  combustion,  as  does  water  which  has  been 
incidentally  added  to  the  fuel. 

Although  carbon  dioxide  and  carbon  monoxide  are 
the  chief  products  of  combustion,  there  are  always  acces- 
sory gases  and  volatile  products  which  also  pass  upward 
in  the  current  that  rises  from  the  fire.  These  have  just 
been  in  part  referred  to,  but  summarily  stated  they  are, 


14  HOUSEHOLD    FUELS 

first,  the  nitrogen  with  which  its  atmospheric  associate, 
oxygen,  has  parted  to  take  the  leading  part  in  combus- 
tion;  second,  water,  which  the  fuel  may  have  acquired 
before  burning;  and  third,  impurities  in  the  air  which  is 
supplied  to  the  burning  fuel.  There  may  also  be  some 
water  originating  as  was  described  in  the  next  preceding 
paragraph. 

All  the  solid  fuels,  hardly  excepting  the  densest 
mineral  coals,  so  readily  absorb  water  from  the  earth 
and  atmosphere  that  some  water  in  the  form  of  vapor 
accompanies  the  products  of  their  combustion,  as  well  as 
the  accompanying  gases,  which  are  invisible,  and  there- 
fore give  one  the  feeling  that  they  have  been  totally 
destroyed.  The  fuel,  as  such,  has  been  destroyed,  but 
each  of  the  elements  of  which  it  was  composed  has  only 
changed  from  one  of  its  conditions  to  another. 

Without  doubt,  also,  the  three  rare,  lately  discovered, 
gaseous  elements  which  are  named  in  the  preceding  chap- 
ter, argon,  helium,  and  neon,  accompany  every  upward 
current  of  fuel  combustion.  There  is  something  impress- 
ive in  the  subjection  of  those  four  quiescent  elements  to 
that  fiery  passage  in  a  process  in  which  they  have  no  part, 
and  whose  destination  is  the  same  condition  as  that  from 
which  they  were  taken.  They  at  least  emphasize  the 
aggressive  action  of  the  oxygen  and  the  greediness  of 
the  hydrogen  and  carbon. 

Ignition.  Because  the  slow  process  of  oxidation 
which  all  fuels  undergo  from  exposure  to  the  atmosphere 
differs  from  combustion  only  in  the  slower  rate  of  its 
progress,  it  needs  only  the  addition  of  fire  to  start  the 
faster  rate,  which  is  called  combustion.  This  initial 


HOUSEHOLD    FUELS  15 

application  of  fire  to  produce  fuel  combustion  is  known 
technically  as  ignition,  but  in  the  household  it  is  known 
as  kindling.  No  matter  how  freely  fuels  will  burn  under 
favoring  conditions,  ignition  of  all  of  them  must  be  begun 
either  by  fires  already  produced,  or  by  the  production  of 
a  small  quantity  of  burning  heat  that  may  be  communi- 
cated by  intermediate  means  to  the  fuelJ^There  is  a  large 
number  of  materials  which  have  been,  or  which  may  be, 
thus  used  for  the  lighting  of  fires,  but  the  friction  match 
now  in  use  is  the  most  convenient  and  effective  of  them 
all.  In  the  following  paragraphs  some  of  the  other 
materials  and  various  methods  of  employing  them  are, 
however,  mentioned  to  show  how  earnestly  man  has 
sought  out  methods  of  replenishing  his  fires.  They  also 
show  what  is  more  to  the  point  for  our  present  purpose, 
that  fires  may  be  produced  by  widely  different  methods. 
A  very  laborious,  but  a  simple  and  direct  primitive 
method  of  kindling  fires  is  by  rubbing  two  narrow  and 
perfectly  dry  pieces  of  readily  combustible  wood  together, 
sometimes  by  holding  the  pieces  at  right  angles  to  each 
other,  and  sometimes  by  holding  them  both  in  the  same 
direction.  Another  primitive  method  of  kindling  by  wood 
friction  is  that  of  rapidly  twirling  a  dry  pointed  stick 
in  a  piece  of  wood  of  the  same  kind,  which  has  been 
slightly  hollowed.  In  all  three  of  these  cases  the  fine 
particles  of  wood  which  are  detached  by  the  friction  take 
fire  from  the  heat  which  is  also  produced  by  it.  In  these 
cases  ignition  of  the  wood  is  accomplished  without  the 
aid  of  any  other  material.  All  three  of  these  methods 
are  very  ancient,  and  their  use  lingers  only  where  friction 
matches  are  difficult  to  obtain,  or  where  the  production 
of  fire  has  been  part  of  a  religious  ceremony. 


1 6  HOUSEHOLD    FUELS 

A  jnethod  of  fire  kindling  which  has  long  been  known, 
and  which  even  now  is  practiced  by  many  savage  and 
semi-civilized  peoples,  is  known  as  that  of  the  fire  piston. 
This  instrument  consists  of  a  small  cylinder  of  horn,  bone, 
or  metal,  a  few  inches  in  length,  less  than  an  inch  in 
diameter,  and  having  a  central  bore.  The  bore  is  closed 
at  the  lower  end,  but  open  at  the  upper  end,  and  is 
usually  less  than  half  an  inch  in  diameter.  The  piston 
is  made  of  the  same,  or  a  similar,  kind  of  material  as  the 
cylinder,  but  longer,  and  fits  the  bore  closely.  A  piece 
of  tinder  is  dropped  into  the  cylinder  and  rests  upon  the 
bottom.  The  piston  is  thrust  into  the  bore  only  so  far 
as  to  steady  it,  and  then  struck  a  smart  blow  upon  its 
upper  end.  The  descent  of  the  piston  compresses  the 
air  in  the  cylinder  so  much  and  so  quickly  that  it  is  made 
hot  enough  to  set  the  tinder  on  fire. 

•  Up  to  one  hundred  years  ago  it  was  not  uncommon 
among  our  people  to  keep  a  "sun  glass,"  which  was  a 
common  lens  of  a  couple  of  inches  in  diameter,  for  prac- 
tical use  in  kindling  fires.  It  was  not  difficult  to  start 
a  fire  by  concentrating  the  sun's  rays  with  such  a  lens, 
but  the  frequent  absence  of  sufficiently  bright  sunshine 
at  the  time  fire  was  needed  made  that  method  of  little 
practical  use. 

The  kindling  of  fire  by  means  of  the  flint  and  steel 
was  perhaps  the  most  widely  used  of  the  methods  which 
were  practiced  before  the  invention  of  friction  matches. 
This  process  is  very  ancient,  and  iron  pyrite  probably 
preceded  steel  in  producing  the  sparks  by  the  flint  stroke. 
It  is  even  now  retained  by  some  savage  peoples  in  regions 
where  that  mineral  is  frequently  found.  When  the  edge 


HOUSEHOLD    FUELS  1 7 

of  a  flake  of  flint  is  struck  obliquely  upon  a  small  bar 
of  hardened  steel,  minute  bits  of  the  steel  are  torn  off 
and  heated  burning  hot  by  the  friction  of  the  stroke  and 
the  ready  action  of  the  oxygen  of  the  air.  These  brilliant 
sparks  are  intensely  hot,  but  they  are  so  small  that  their 
heat  is  quickly  lost,  and  they  would  therefore  be  useless 
if  they  were  not  made  to  fall  upon  some  easily  ignited 
material.  Such  material  is  called  tinder,  and  may  be  of 
various  kinds. 

The  kind  of  tinder  which  was  most  commonly  used 
in  our  colonial  households  and  in  those  of  still  later  date 
was  made  by  the  charring  of  pieces  of  cotton  or  linen 
cloth,  which  process  changed  the  cloth  to  fibrous  char- 
coal. The  delicate  fibers  of  this  charcoal  tinder  instantly 
catch  the  hot  sparks  as  they  fall  from  the  steel,  and 
produce  little  burrowing  patches  of  sparks  of  their  own 
among  the  threads.  Rural  housekeepers  also  occasionally 
used  other  substances  for  tinder,  among  which  was  a 
fibrous  kind  of  decayed  wood  mingled  with  a  fungous 
growth,  and  called  "spunk"  or  "punk."  Hunters  and 
travelers  sometimes  used  still  other  kinds  of  tinder,  but 
the  charred  cloth  was  superior  to  all  other  kinds,  and  the 
tinder  box  in  which  it  w^as  kept  was  one  of  the  chief 
household  conveniences. 

With  great  care  it  is  possible  to  ignite  fine  wood 
kindlings  directly  from  the  burning  tinder,  but  usually 
the  amount  of  fire  which  is  produced  in  tinder  is  too 
small  for  such  ignition,  and  an  intermediary  substance 
for  the  transfer  of  the  fire  is  necessary.  For  this  purpose 
the  sulphur  match  was  used.  It  was  generally  known 
as  the  "brimstone  match,"  and  was  also  made  in  the 
household. 


1 8  HOUSEHOLD    FUELS 

Sulphur  is  a  distinct  chemical  element,  but,  although 
combustible,  it  is  not  a  fuel.  It  melts  at  a  comparatively 
low  temperature,  ignites  from  a  spark  if  only  a  minute 
quantity  is  applied,  and  burns  with  a  bluish,  smoky  flame. 
The  match  was  a  slender  piece  of  soft  wood,  one  end 
of  which  was  narrowed  nearly  to  a  point  and  dipped  in 
melted  sulphur.  The  latter  was  therefore  called  the  dip, 
a  term  which  has  been  continued  in  use  for  the  corre- 
sponding application  to  friction  matches.  The  small 
prepared  end  of  the  suphur  match  was  applied  to  the 
sparks  among  the  tinder,  arid  it  quickly  became  ignited. 
The  sulphur  flame  at  once  set  the  hydrogen  of  the  match 
aflame,  which  was  then  ready  to  be  applied  to  the  candle, 
lamp,  or  kindling  wood,  as  we  now  apply  the  common 
friction  match. 

Early  in  the  nineteenth  century  a  dip  was  invented 
which  would  ignite  when  the  prepared  end  of  the  match 
was  thrust  into  sulphuric  acid  contained  in  a  small  bottle, 
and  quickly  withdrawn.  That  method  was  not  of  con- 
venient use,  and  the  invention  was  soon  followed  by  that 
of  a  dip  which  would  ignite  by  friction. 

Friction  Matches.  Several  partial  successes  in  the 
manufacture  of  friction  matches  were  made  before  the 
practical  success  of  the  one  which  was  really  the  direct 
lineal  descendant  of  the  brimstone  match.  That  is,  the 
first  really  successful  friction  matches  that  came  into 
general  use  were  common  sulphur  matches,  each  of  which 
had  received  a  second  coating  of  another  kind  of  dip 
over  its  sulphur  end,  which  would  ignite  by  friction  on 
a  moderately  rough  surface.  Matches  of  this  simple  kind 
are  still  in  use  in  some  parts  of  our  country. 


HOUSEHOLD    FUELS  IQ 

Many  modifications  of  that  primitive  frictional  dip 
have  been  made,  with  the  purpose  of  abandoning  the  use 
of  unwholesome  or  dangerous  materials  which  it  con- 
tained, besides  others  since  used.  Among  the  substances 
that  have  been  used  in  the  preparation  of  the  dip  are 
sulphur,  phosphorus,  mercury,  antimony,  and  the  nitrates 
of  potassium  and  sodium,  besides  adhesive  and  other 
ingredients.  The  evil  effects  of  some  of  these  substances 
upon  the  health  of  those  persons  who  are  employed  in 
the  match  manufacture  are  so  great  that  effort  has  been 
made  to  enforce  their  abandonment. 

The  invention  of  the  so-called  safety  match  has  much 
diminished  the  danger  attending  the  general  use  of  fric- 
tion matches,  and  has  at  least  partially  lessened  that  which 
has  long  attended  their  manufacture.  The  dip  on  these 
matches  consists  of  a  mixture  that  only  with  great  diffi- 
culty can  be  made  to  ignite  by  friction  upon  any  surface 
except  those  which  have  a  specially  prepared  substance 
spread  upon  them.  Ignition  of  the  dip  material  of  these 
matches  is  caused  by  chemical  reaction  between  the  con- 
tents of  the  dip  and  those  of  the  surface  preparation, 
which  must  be  incited  by  friction.  In  the  case  of  the 
common  friction  match,  friction  alone  produces  enough 
heat  to  ignite  the  dip  material ;  but  in  the  case  of  the 
safety  match,  although  friction  is  necessary,  the  character 
of  the  dip  is  such  that  it  will  not  ignite  without  the 
aid  of  an  accessory  substance.  Because  matches  are  so 
generally  used  and  so  constantly  within  the  reach  of 
every  one,  even  of  children,  it  is  evident  that  some  such 
regulation  as  prevails  with  reference  to  kerosene  should 
restrict  the  use  of  matches  to  some  safety  form.  Every 


2O  HOUSEHOLD    FUELS 

housekeeper  should  insist  on  having  no  other  kind  in  the 
household. 

Without  statistical  information  one  is  hardly  prepared 
to  realize  the  extent  of  business  operations  which  are 
involved  in  the  manufacture  of  matches  in  our  own  and 
other  countries.  A  reputable  magazine  recently  published 
the  statement  of  a  competent  author  that  seven  hundred 
thousand  millions  of  friction  matches  are  used  by  the 
people  of  the  United  States  every  year.  One  cannot 
doubt  that  the  proportion  used  in  other  countries  is  quite 
as  great.  This  little,  familiar  article  alone,  which  we  use 
and  waste  so  carelessly,  makes  an  enormous  draft  upon 
the  world's  supply  of  wood  which  must  soon  call  for 
national  remedy  in  the  planting  and  protection  of  forest 
trees  of  suitable  kinds  for  its  manufacture. 

Flame  Combustion.  Mention  has  already  been 
made  of  the  combustion  of  the  solid  fuels,  but  because 
the  flame  fuels  are  to  be  described  separately  in  the  fol- 
lowing chapters,  consideration  of  flame  combustion  is 
brought  forward  in  this  chapter  that  it  might  follow  the 
discussion  of  ignition.  X  The  flame  of  all  the  lighting 
fuels  consists  of  hydrogen  and  carbon,  and  when  they 
are  burned  the  hydrogen  is  the  first  to  ignite.  Hydrogen, 
when  pure,  burns  with  a  faint  bluish  flame  which  gives 
very  little  light,  but  in  fuel  flames  hydrogen  is  always 
associated  with  exceedingly  fine  particles  of  carbon,  which 
are  heated  to  the  glowing  point  by  the  burning  hydrogen. 
It  is  this  glowing,  or  incandescence,  of  the  carbon  which 
gives  the  yellowish  or  ruddy  light  to  the  flames. 

The  Candle  Flame.  Among  our  immediate  ances- 
tors the  candle  flame  was  so  distinctly  associated  with 


HOUSEHOLD    FUELS  21 


the  affairs  of  their  every-day  life  that  its  name  was  used 
to  indicate  the  time  of  its  lighting.  For  example,  notices 
of  public  meetings  were  habitually  given  to  occur  at 
"candle-light"  or  "early  candle-light,"  meaning  approach- 
ing nightfall,  or  twilight.  *This  flame  has  the  same 
chemical  composition  as  the  flame  of  the  solid  fuels,  but 
because  of  its  symmetrical  shape  and  nearly  uniform  size 
.it  has  long  been  regarded  not  only  as  the  typical  house- 
hold light,  but  the  accepted  unit  of  measurement  of  the 
quantity  of  light  which  is  given  off  by  other  flames  or 
other  methods.  Reduced  to  exact  limits,  that  unit  and 
its  name  are  still  used,  even  in  scientific  estimates  and 
specifications. 

In  the  candle  flame  also  is  to  be  observed  the  manner 
of  combustion  of  the  chemical  elements  of  which  the 
candle  is  composed.  To  illustrate  these  methods  suitably, 
the  candle  must  be  made  of  one  of  the  semi-solid  fuels 
which  is  hard  enough  at  ordinary  temperatures  for 
cleanly  and  convenient  handling,  and  pure  enough  to 
change  readily  to  an  oily  substance  and  then  to  a  gaseous 
condition,  without  residue,  when  heat  is  applied.  The 
candle  is  composed  of  carbon,  hydrogen,  and  oxygen, 
and,  as  in  all  similar  combinations,  this  structural  oxygen 
is  believed  to  be  inert  during  combustion.  That  is,  the 
combustion  of  the  carbon  and  hydrogen  is  accomplished 
by  the  oxygen  of  the  air  only.  When  the  wick  of  the 
candle  is  lighted,  the  heat  of  the  flame  melts  a  portion 
of  the  candle  to  an  oily  condition,  which  then  rises  by 
capillary  action  to  the  burning  portion  of  the  wick,  where 
it  is  changed  to  a  gaseous  state.  It  is  the  increased  heat 
which  occurs  there  that  causes  the  change  from  a  liquid 


22  HOUSEHOLD    FUELS 

to  a  gas,  and  it  is  the  combustion  of  this  gas  that  gives 
the  flame. 

Within  the  basal  part  of  the  flame  there  is  a  space 
•which  appears  dark  by  contrast  with  the  next  outer 
portion.  This  dark  portion  of  the  flame  consists  of  un- 
consumed  gas,  to  which  that  portion  of  the  candle  that 
was  changed  to  a  liquid  condition  is  further  changed 
by  the  higher  heat  which  it  there  encounters.  The  lumi- 
nous envelope,  which  constitutes  the  principal  part  of  the 
flame,  surrounds  this  dark  portion.  This  luminous 
envelope  is  the  gas  in  its  first  stage  of  combustion,  where 
the  hydrogen  and  part  of  the  carbon  are  chemically 
united  with  oxygen  derived  from  the  air.  The  remainder 
of  the  carbon  is  quickly  heated  until  it  glows,  which 
condition  is  known  as  incandescence.  As  the  incandes- 
cent particles  of  carbon  within  the  flame  pass  outward 
where  oxygen  from  the  air  has  free  access,  many  of  them 
so  unite  with  the  oxygen  as  to  form  carbon  dioxide, 
which  passes  off  into  the  air.  The  part  of  the  flame  in 
which  this  last  named  union  takes  place  is  the  outermost 
part,  and  is  known  as  the  mantle.  It  is  so  slightly  lumi- 
nous as  to  be  almost  invisible,  but  it  is  the  hottest  part 
of  the  flame. 

Some  particles  of  ununited  carbon  constantly  escape 
from  all  flames,  the  effect  of  which  is  often  seen  on  the 
white  ceiling  above  a  gas  jet.  Also,  if  a  porcelain  dish 
is  held  for  only  a  moment  in  the  luminous  part  of  the 
flame  it  becomes  blackened.  This  black  deposit  is  carbon, 
a  part  of  which  had  become  incandescent,  but  was  sud- 
denly cooled  by  the  porcelain  dish  and  deposited  upon 
its  surface.  Any  interference  with  the  flame  is  likely  to 


HOUSEHOLD    FUELS  23 

cause  it  to  smoke.  'This  smoke  consists  of  fine,  escaping 
particles  of  carbon. 

Lamp  Flames.  The  flame  of  a  lamp  having  the 
ordinary  twisted  or  braided  wick  is  like  the  candle  flame 
in  structure,  shape,  and  manner  of  combustion.  The 
fuel  in  the  lamp  is  already  liquid,  otherwise  the  stages 
in  the  process  of  producing  the  flame  are  the  same  as  in 
the  case  of  the  candle.  The  flame  of  the  alcohol  lamp, 
however,  gives  no  smoke,  because  of  the  complete  com- 
bustion of  its  carbon ;  but  the  flame  of  the  oils,  especially 
of  the  mineral  oils,  although  burned  in  good  lamps,  is 
much  inclined  to  smoke.  This  objectionable  character  of 
those  oils  is  due  to  the  large  proportion  of  carbon  which 
they  contain,  some  of  which  escapes  oxidation.  This  evil 
has  been  remedied  to  a  great  extent  by  flattening  and 
otherwise  changing  the  shape  of  the  wick  tubes  so  as  to 
present  a  greater  surface  of  the  flame  to  the  air,  and 
by  providing  devices  for  directing  currents  of  air  against 
the  flame.  Among  the  most  effective  of  these  devices 
is  the  cylindrical  wick,  which  produces  a  flame  of  like 
shape  and  allows  a  current  of  air  to  pass  up  along  the 
inside  of  it  as  well  as  the  outside.  The  large  cylindrical 
glass  chimneys,  through  which  a  strong  current  of  air 
will  pass  upward  and  be  directed  against  the  flame  on  all 
sides,  very  much  improve  the  combustion  of  these  highly 
carbonized  fuels. 

Gas  Flames.  The  structure  of  the  gas  flame  is  the 
same  as  that  of  the  candle  and  oil  flames.  It  has  the  same 
central  dark  portion,  the  luminous  envelope,  and  the 
almost  invisible  mantle.  Unlike  those  flames,  however, 
the  gas  in  this  case  is  already  prepared  and  ready  for 


24  HOUSEHOLD    FUELS 

use  without  any  intermediary  process.  The  gas  is  con- 
stantly supplied  to  the  burners  by  the  force  which  sends 
it  from  the  gas  works.  When  that  pressure  is  too  great, 
the  gas  rushes  through  the  burner  so  rapidly  that  un- 
consumed  carbon  is  especially  liable  to  escape,  because 
it  has  not  sufficient  time  for  complete  incandescence  and 
oxidation.  That  excessive  flow  should  be  checked  at 
once,  because  it  wastes  the  .gas,  diminishes  the  light, 
sends  unconsumed  carbon  into  the  atmosphere  of  the 
room,  and  produces  more  or  less  carbon  monoxide  by 
incomplete  combustion.  The  small  apertures  of  the 
burners  are  placed  opposite  each  other  to  so  spread 
the  flame  that  it  will  present  two  broad  surfaces  to  the 
air.  A  large  and  efficient  cylindrical  flame  is  sometimes 
produced  from  a  burner  consisting  of  a  circle  of  small 
apertures,  surmounted  by  a  glass  chimney.  But  even 
under  favorable  conditions  gas  flames  are  liable  to  more 
or  less  variation  in  efficiency. 

If  the  amount  of  air  admitted  to  the  burning  gas  is 
much  too  small,  the  result  is  a  smoky  flame.  If  the 
amount  is  great  enough  for  the  full  oxidation  of  the 
carbon  before  it  has  had  sufficient  time  for  complete 
incandescence,  the  result  is  diminished  light.  If  a  large 
amount  of  air  is  admitted  to  the  fuel  in  its  gaseous  con- 
dition, before  it  reaches  the  flame,  the  increased  amount 
of  oxygen  which  that  air  brings  oxidizes  all  the  carbon 
immediately,  the  incandescent  stage  being  omitted  from 
the  flame  in  this  case.  The  result  is  intense  heat,  but  no 
serviceable  light.  A  burner  meeting  the  requirements 
of  complete  incandescence  of  all  the  carbon  of  the  gas 
passing  through  it  without  complete  oxidation  has  not 


HOUSEHOLD    FUELS  25 

yet  been  produced,  but  other  incandescent  lights  of  re- 
markable efficiency  have  been  invented. 

The  Mantle,  or  Incandescent  Light.  These  de- 
vices, which  produce  a  strong  and  equable  light,  much 
superior  to  that  of  the  most  brilliant  flame  of  ordinary 
gas,  accomplish  it  by  the  incandescence,  not  of  the  carbon 
of  gas,  but  of  a  material  entirely  unconnected  with  it. 
It  is  true  that  this  light  is  produced  by  means  of  a  flame 
of  ordinary  gas,  but  the  only  office  of  the  flame  in  this 
case  is  the  production  of  heat.  A  blue  gas  flame  is  pro- 
jected upon  a  small,  delicately  woven,  basket-like  struc- 
ture, called  a  mantle,  causing  its  instant  and  complete 
incandescence,  and  producing  thereby  an  intense,  steady, 
and  pleasant  light.  In  the  construction  of  these  fragile 
mantles  several  kinds  of  the  earthy  minerals  have  been 
tried,  all  of  which  resist  excessive  heat,  but  thorium  is 
the  one  which  is  understood  to  be  the  most  commonly 
used.  It  is  the  mantle  only  that  becomes  luminous  ;  the 
gas  itself  gives  no  perceptible  light.  This  mantle  light 
is  far  more  intense  than  can  be  obtained  from  incandes- 
cent carbon  under  any  circumstances.  The  mantle  of  this 
light  must  not  be  confounded  with  the  mantle  of  the 
candle  flame.  They  have  no  connection  with  each  other 
except  their  unfortunate  identity  of  name. 


CHAPTER    IV 

THE    SOLID    FUELS:    MINERAL    COALS, 
COKE,    AND    PEAT 

'  I  M-IE  solid  fuels  generally  are  used  only  to  produce 
-•-  heat,  and  not  light.  One  of  them,  however,  bitu- 
minous coal,  is  used  in  the  making  of  illuminating  gas, 
and  large  quantities  of  similar  gas  are  obtained  from 
other  mineral  coals.  Moreover,  anthracite  is  almost  in- 
dispensable in  the  production  of  water  gas,  as  we  shall 
see  in  a  following  chapter,  but  in  this  chapter  we  will 
consider  only  the  character  of  the  solid  fuels  as  heat 
fuels. 

The  most  concentrated  of  all  the  solid  fuels  are  the 
various  kinds  of  mineral  coal.  These  coals  differ  in  kind 
from  one  another,  but  every  kind  is  important.  There 
is  no  reason  to  doubt  that  the  method  by  which  the 
mineral  coals  have  originated  was  essentially  the  same 
for  all  of  them.  It  is  believed  that  their  differences  are 
largely  due  to  the  conditions  under  which  they  were 
mineralized.  Doubtless  all  coals  were  at  one  time  in  a 
condition  similar  to,  if  not  identical  with,  that  of  peat, 
so  that  the  method  of  their  origination  may  be  illustrated 
by  the  statement  immediately  following;  but  peat  as  a 
fuel  will  be  described  in  a  still  later  paragraph. 

The  Origin  of  Peat.  Peat  is  in  a  soft,  somewhat 
plastic  condition  as  it  exists  in  most  of  the  older  and 
deeper  deposits,  and  of  a  somewhat  spongy  texture  nearer 

26 


HOUSEHOLD    FUELS  2/ 

the  top.  It  varies  in  color  from  a  light  to  a  dark  brown, 
and  is  frequently  interspersed  with  roots  and  vegetable 
fiber.  It  consists  of  the  remains  of  mosses,  sedges,  and 
other  herbaceous  plants  which  grow  in  bogs  or  on  marshy 
ground  and  at  the  shallow  borders  of  ponds.  As  these 
plants  mature  in  the  autumn,  they  fall  down  and  are 
covered  by  the  water  in  or  upon  the  margin  of  which 
they  grow,  and  also  by  the  successive  annual  accumula- 
tions of  the  same  kind  of  materials.  The  atmosphere 
is  excluded  from  the  fallen  plants  by  the  water,  and  they 
therefore  do  not  decay  as  they  would  if  they  were  to 
fall  upon  ordinary  ground.  Destructive  decay  of  the 
accumulating  vegetable  matter  is  further  prevented  by 
antiseptic  properties  which  forming  peat  possesses. 
From  year  to  year  the  accumulations  of  peat  thus  pro- 
ceed, adding  to  its  quantity  and  increasing  the  limits  and 
depth  of  the  bog.  The  plasticity  of  peat  also  increases 
with  age,  and  in  wet  seasons  the  bog  is  liable  to  burst 
its  bounds  and  flood  the  adjacent  cultivated  land  with 
flowing  peat.  Well-preserved  trunks  of  large  trees  have 
been  found  buried  in  peat  bogs,  that  grew  in  prehistoric 
times  and  were  probably  killed  and  overthrown  in  that 
way.  The  presence  of  water  in  the  formation  of  peat 
is  so  necessary  that  it  is  never  found  in  arid  regions,  and 
the  largest  bogs  now  known  are  in  the  northern  countries 
of  Europe.  Deposits  of  peat  are  often  very  small,  the 
more  important  of  them  ranging  from  a  few  hundred 
acres  to  two  or  three  thousand  acres.  But  even  the  latter 
are  small  as  compared  with  beds  of  coal. 

The  Origin  of  Mineral  Coal.     There    is    no    doubt 
in  the  minds  of  geologists  that  all  the  various  kinds  of 


28  HOUSEHOLD    FUELS 

mineral  coal  are  of  vegetable  origin  as  regards  the  fuel 
substances  of  which  they  are  composed.  Although  all 
the  conditions  under  which  mineral  coal  exists  in  the 
earth  today  are  not  fully  explained  by  the  known  origin 
of  peat,  that  theory  of  its  origin  is  generally  accepted. 
This  view  of  the  origin  of  the  mineral  coals  implies  that 
during  the  ages  which  have  passed  since  the  deposits 
accumulated  as  peat,  disturbances  of  the  earth  have 
caused  them  to  sink  beneath  bodies  of  water  and  to 
become  covered  with  sedimentary  materials  which  in  the 
course  of  time  changed  to  rocky  strata.  This  view 
further  implies  that  the  peaty  matter,  by  sharing  in  the 
earth's  changes  which  affected  the  rocky  strata,  became 
changed  to  coal. 

There  are  other  facts  besides  those  upon  which  the 
theory  of  its  peaty  origin  is  based  which  justify  one  in 
attributing  a  vegetable  origin  to  all  kinds  of  mineral  coal. 
Coal  consists  of  the  same  fuel  elements  that  are  found 
in  wood  and  peat,  and  it  differs  from  all  other  substances 
found  in  the  earth  by  being  subject  to  true  fuel  com- 
bustion. Fossil  remains  of  plants  are  often  found  in 
greater  or  less  abundance  in  the  layers  of  rock  or  shale 
which  underlie  and  overlie  the  beds  of  coal,  and  some- 
times they  are  found  in  the  coal  itself.  Even  in  anthra- 
cite, the  hardest  and  most  compact  of  all  the  coals,  faint 
traces  of  vegetable  structure  have  been  found.  It  is 
believed  that  all  these  plant  remains  belonged  to  a  great 
growth  of  vegetation  of  which  each  deposit  of  coal  was 
formed. 

It  is  only  in  a  part  of  the  geological  formations  that 
mineral  coal  is  found,  and  in  some  regions  of  the  earth 


HOUSEHOLD    FUELS  2Q 

no  trace  of  it  has  been  discovered.  Still,  there  are  only 
a  few  countries  in  which  some  kinds  of  mineral  coal  have 
not  been  found.  Those  districts  or  regions  in  which  coal 
is  known  to  exist  beneath  the  surface  are  usually  called 
coal  fields.  Some  of  the  coal  fields  are  hiany  square 
miles  in  extent,  while  many  are  smaller.  The  coal  is 
found  in  beds,  or  layers,  which  vary  from  a  few  inches 
to  several  feet  in  thickness,  and  in  many  coal  fields 
separate  beds  occur,  at  different  depths  from  the  surface. 
The  beds  are  often  of  great  extent,  but  the  depth  at 
which  they  lie  has  no  definite  relation  to  the  surface  of 
the  overlying  earth.  •  As  a  rule,  beds  of  coal  are  parallel, 
or  conformable,  with  the  layers  of  rock,  shale,  or  clay 
which  lie  above  or  beneath  them.  In  some  cases  the  coal 
and  its  associated  rocky  layers  have  been  so  disturbed 
by  the  earth's  movements  that  they  lie  at  various  angles 
with  the  horizon,  but  in  other  cases  they  are  nearly 
horizontal.  In  all  cases  mineral  coal  is  obtained  with 
great  labor,  and  often  with  great  risk  to  human  life. 

The  mineral  coals  differ  much  in  character  and  quality 
in  different  regions  and  in  different  mines,  even  when 
they  bear  the  same  name.  Some  of  them  are  therefore 
more  suitable  than  others  for  household  purposes,  a  fact 
which  should  always  be  borne  in  mind  when  coal  is 
bought.  Besides  the  vague  terms  "hard"  and  "soft," 
which  are  commonly  used  by  dealers  for  the  mineral 
coals,  there  are  more  definite  terms  generally  used  in  the 
markets.  Still,  it  is  difficult  to  designate  by  name  all 
varieties  of  coal,  because  different  names  for  the  same 
variety,  and  the  same  name  for  different  varieties,  are 
often  used  by  dealers  and  people  of  different  cities.  The 


3O  HOUSEHOLD    FUELS 

names  anthracite,  bituminous,  semi-bituminous,  non- 
bituminous,  cannel,  and  lignite  have  long  been  in  com- 
mon use,  and,  although  not  entirely  satisfactory,  they 
are  chosen  for  the  present  purpose. 

Anthracite.  Of  all  mineral  coals  and,  in  fact,  of 
all  fuels,  there  is  no  more  valuable,  or  more  acceptable, 
fuel  for  heating  purposes  than  anthracite.  It  is  the  most 
compact  and  firm  in  texture  of  all  the  mineral  coals, 
and  well  deserves  its  popular  name  of  "hard  coal."  It 
can  be  broken  into  pieces  of  any  desired  size ;  it  breaks 
with  a  smooth,  bright  fracture,  and  is  not  inclined  to 
crumble  when  handled  or  exposed  to  the  air.  When  free 
from  mine  dust  it  is  the  cleanest  of  all  coals,  and  it  has 
a  pleasing,  uniform  black  color.  It  burns  with  little  or 
no  flame  because  of  the  lack  of  hydrogen  in  its  compo- 
sition, but  when  provided  with  a  good  draft  it  burns 
with  a  cheerful  glow.  It  consists  more  nearly  of  pure 
carbon  than  do  any  of  the  other  coals.  It  burns  with 
a  more  intense  and  steady  heat,  and  for  a  longer  time 
without  replenishing,  than  do  any  of  the  others.  There- 
fore, considered  bulk  for  bulk,  it  is  the  most  economical 
of  all  the  fuels.  Although  there  is  a  considerable  pro- 
portion of  ashes  left  after  burning  even  the  best  anthra- 
cite, its  ashes  are  generally  free  from  those  hard  lumps 
called  clinkers,  which  are  common  in  some  other  coals. 

With  such  a  good  record  of  qualities,  one  naturally 
regrets  that  anthracite  forms  only  a  small  proportion 
of  the  coal  supply  of  the  world.  Most  of  that  which  is 
produced  in  America  is  obtained  from  a  field  in  Pennsyl- 
vania which  occupies  only  a  small  part  of  the  state. 
The  next  most  important  anthracite  fields  now  known 


HOUSEHOLD    FUELS  3! 

are  in  Great  Britain,  but  it  is  believed  that  large  quanti- 
ties of  this  valuable  fuel  exist  in  China. 

Bituminous  Coal.  This  coal,  although  of  a  decided 
stony  hardness,  is  popularly  called  "soft  coal,"  probably 
because  it  crumbles  so  easily  when  handled  or  when 
exposed  to  the  weather,  or  perhaps  in  contrast  with 
anthracite,  which  is  commonly  called  hard  coal.  Bitu- 
minous coal  contains  a  considerable  proportion  of  hydro- 
gen, and  for  that  reason  it  gives  off  flames  freely  when 
its  fires  are  first  made,  after  which  its  large  amount  of 
carbon  appears  as  a  glowing  bed  of  embers,  which 
produces  great  heat. 

Bituminous  coal  is  distinguished  from  other  coals 
in  two  important  respects,  namely,  from  it  is  produced 
the  highest  grade  of  both  illuminating  gas  and  coke. 
The  former  comes  from  its  abundant  hydrogen,  together 
with  some  of  its  carbon,  and  the  latter  from  its  carbon 
alone.  Further  mention  will  be  made  of  both  the  gas 
and  coke  on  following  pages.  Bituminous  coal  is  some- 
times called  caking  coal,  because  a  cake,  or  crust,  is 
often  formed  on  it  when  burning.  This  cake  is  really 
coke,  and  its  formation  when  burning  distinguishes  the 
coal  producing  it  from  other  coals  which  have  a  similar 
appearance.  When  bituminous  coal  is  burned  in  an  open 
grate  it  can  be  seen  to  fuse  more  or  less  completely  into 
a  pitchy,  bubbling  mass,  which  is  due  to  the  bituminous 
character  of  a  part  of  its  substance.  At  the  same  time 
it  gives  off  much  flame  and  smoke.  It  is  this  portion 
of  the  coal  that  forms  the  cake  which  has  just  been 
mentioned,  and  being  reduced  to  comparatively  pure 
carbon  by  the  continued  heat,  it  is  consumed  with  the 
other  carbon  of  the  coal. 


32  HOUSEHOLD    FUELS 

More  smoke  is  produced  by  bituminous  coal  than 
by  any  of  the  other  mineral  coals,  unless  the  fires  are 
carefully  managed,  especially  by  having  a  good  draft 
and  adding  new  coal  to  the  fire  in  small  quantities 
before  it  has  burned  too  low.  This  tendency  to  smoke 
when  burning,  and  the  large  accumulation  of  dirty  dust 
among  the  broken  pieces  of  bituminous  coal,  impairs  its 
value  as  a  household  fuel.  Still,  it  is  in  some  respects 
one  of  the  most  valuable  coals  in  use. 

A  large  proportion  of  all  the  mineral  coals,  not  only 
in  our  country,  but  in  the  world  generally,  have  much 
the  same  aspect  as  bituminous  coal,  but  they  lack  the 
superior  quality  for  gas  and  coke  making  which  that 
coal  possesses. 

Coke.  Mention  is  made  of  coke  in  this  connection 
because  it  is  the  solid  fuel  product  of  bituminous  coal. 
The  gaseous  product  of  that  coal  will  be  discussed 
among  the  gaseous  fuels.  When  bituminous  coal  is 
placed  in  closed  retorts,  each  of  which  is  provided  with 
an  escape  pipe  and  highly  heated  by  fires  burning  under- 
neath, it  is  not  consumed,  because  no  air  can  enter  the 
retort  to  furnish  the  necessary  oxygen  to  unite  with 
the  carbon.  The  heat  is  continued  and  the  coal  becomes 
a  partially  melted,  bubbling  mass,  and  its  volatile  parts 
all  pass  off  as  gas  by  the  way  of  the  escape  pipes.  When 
the  retorts  are  cooled  the  residue  which  is  left  in  them 
is  coke,  a  valuable  fuel,  which  is  almost  pure  carbon. 
The  use  of  those  retorts  for  gas  making  is  explained 
in  Chapter  VIII,  under  the  head  of  Coal  Gas. 

Coke  has  a  grayish,  semi-metallic  luster,  and  is  light 
and  porous.  This  porous  condition  is  due  to  the  minute 


HOUSEHOLD    FUELS  33 

bubbles  of  gas  which  formed  when  the  coal  was  in  a 
partially  melted  condition.  Coke  burns  without  flame, 
and  as  a  heat  producer  the  best  quality  of  it  is  equal 
to  anthracite,  in  equal  weight.  The  coke  which  is  made 
for  special  use  in  the  industrial  arts  is  generally  of  the 
best  quality  obtainable  in  the  markets.  The  major  part 
of  the  coke  found  in  the  fuel  markets  comes  from  the 
retorts  of  the  gas  works,  and  the  quality  is  not  quite  so 
good  as  that  of  the  other  just  mentioned.  Coke  is  a 
very  acceptable  household  fuel  for  summer  use,  as  it  is 
clean  and  burns  freely.  It  is  usually  sold  by  measure 
and  not  by  weight.  This  custom  is  probably  due  to  its 
tendency  to  increase  its  weight  by  absorbing  water, 
which  has  been  known  to  reach  twenty-five  per  cent. 

Semi-Bituminous  Coal.  This  variety  of  mineral 
coal  is  similar  in  appearance  to  bituminous  coal,  but  it 
shows  little  of  the  character  of  that  coal  when  burning, 
as  it  produces  much  less  flame,  and  the  amount  of  gas 
which  may  be  obtained  from  it  is  very  small.  It  is  more 
cleanly  to  handle  than  bituminous  coal,  but  not  so  cleanly 
as  anthracite.  Its  free-burning  quality,  as  compared 
with  the  latter  coal,  makes  it  a  desirable  fuel  for  special 
household  purposes.  That  which  is  sold  in  the  markets 
is  found  in  the  region  adjacent  to  the  Pennsylvania 
anthracite  field,  and  it  is  often  sold  under  the  name  of 
the  mine  which  produces  it. 

In  accordance  with  the  generally  accepted  theory 
of  the  origin  of  mineral  coals,  it  is  believed  that  in 
some  cases  after  bituminous  coal  was  formed  it  was 
changed  by  some  natural  process  by  which  it  parted 
with  its  hydrogen  and  became  anthracite.  In  accord- 


34  HOUSEHOLD    FUELS 

ance  with  this  view  it  is  believed  that  semi-bituminous 
coal  represents  an  intermediate  condition  between 
bituminous  coal  and  anthracite. 

Non-Bituminous  Coal.  Under  this  head  may  be 
ranged  much  the  larger  part  of  the  mineral  coals  of  the 
world,  all  of  them  having  the  general  aspect  as  well  as 
the  black  color  of  bituminous  coal.  Xone  of  them, 
however,  produces  good  coke  as  compared  with  that  of 
bituminous  coal,  and  few  of  them  are  good  gas  coals, 
even  when  they  are  efficient  heat  fuels.  Notwithstand- 
ing those  deficiencies,  the  best  of  them  are  among  the 
most  acceptable  of  household  fuels.  The  many  varieties 
of  non-bituminous  coal  are  not  readily  distinguishable  by 
name,  and  it  has  become  customary  to  give  them  the 
local  names  of  the  mines  or  places  from  which  they 
are  obtained. 

Cannel  Coal.  This  coal  is  usually  dull  black  in 
color,  but  its  blackness  is  sometimes  intense.  It  is  of  a 
more  or  less  uniformly  compact  texture,  without  the 
numerous  cross  fractures  which  are  so  common  with 
other  coals,  and  it  is  therefore  not  much  inclined  to 
crumble  upon  exposure.  Some  varieties  are  so  dense 
and  black  that  it  has  been  used  for  the  manufacture  of 
articles  sold  as  jet.  It  burns  freely,  with  much  flame, 
which  often  assumes  the  shape  of  candle  flames.  This 
fact  gave  origin  to  the  name,  which  is  a  corruption  of 
candle  coal.  It  ignites  so  easily  that  it  may  often  be 
lighted  directly  from  a  match,  and  because  of  this  con- 
venience and  the  pleasing  effect  of  the  flames  it  has  been 
much  esteemed  for  use  in  open  fireplaces.  Illuminating 
gas,  mineral  oil,  and  paraffin  have  been  obtained  from 


HOUSEHOLD    FUELS  35 

cannel  coal,  but  its  average  value  is  not  so  great  as  that 
of  some  other  mineral  coals. 

True  cannel  coal  is  not  found  in  large  quantities  in 
our  country,  although  dealers  often  sell  other  blazing 
coals  under  that  name.  Limited  deposits,  however,  have 
been  found  in  the  carboniferous  strata  of  some  of  the 
interior  states,  but  the  beds  which  have  been  found  are 
too  thin,  and  the  quality  of  the  coal  too  poor  to  pay  for 
mining. 

Lignite.  Owing  to  the  brown  color  of  true  lignite 
it  is  often  called  brown  coal.  This  fuel  is  found  in  the 
earth,  as  are  the  mineral  coals  already  described,  and 
its  texture  resembles  that  of  both  mineral  coal  and  peat. 
In  true  lignite  more  or  less  woody  and  herbaceous  fiber 
is  distinguishable,  which  shows  that  trees,  as  well  as 
herbaceous  plants,  entered  into  its  original  peaty  com- 
position, and  it  is  the  presence  of  this  woody  fiber  that 
gave  this  coal  its  name.  Although  the  best  lignite  burns 
freely,  its  fuel  value  seems  to  be  very  little  greater  than 
that  of  the  best  of  peat.  Very  little  true  lignite  has 
been  found  in  our  country,  and  it  need  not  be  discussed 
as  an  American  household  fuel.  It  has  been  found 
mostly  in  Europe,  but  the  term  lignite  has  often  been 
applied  to  some  of  the  poorer  non-bituminous  American 
coals,  especially  to  some  of  those  which  have  been  found 
in  the  western  parts  of  the  United  States  and  Canada. 

Peat.  Although  peat  is  commercially  one  of  the 
least  valuable  of  our  fuels,  it  is  given  general  mention 
with  the  others  because  of  its  assumed  relation  to  the 
origin  of  the  mineral  coals,  and  of  its  importance  as  a 
fuel  in  certain  regions  where  other  fuels  are  not  avail- 


36  HOUSEHOLD    FUELS 

able.  Peat  deposits,  unlike  those  of  mineral  coal,  have 
no  covering  except  the  accumulation  of  moss  and  fallen 
vegetation  which  grew  there,  and  which  have  not  had 
sufficient  time  to  change  to  peat. 

The  process  of  harvesting  peat  is  simple,  but  labori- 
ous and  dirty.  The  surplus  water  is  first  drained  from 
the  bo«f  and  its  covering  of  dead  vegetation  thrown  aside 

o  o  o 

with  shovels.  Then  another  kind  of  shovel,  the  blade 
of  which  is  bent  longitudinally  at  right  angles,  is  used 
to  cut  the  soft  peat  into  angular  blocks.  These  blocks 
are  dried  in  the  open  air,  just  as  freshly  molded  building 
bricks  are  dried  before  they  are  stacked  in  the  kiln,  and 
the  peat  is  ready  for  use. 

Even  when  carefully  dried  and  stored,  peat  thus 
prepared  is  liable  to  crumble  by  handling,  and  in  that 
condition  it  makes  a  poor,  smoldering  fire.  Many  efforts 
have  been  made  to  improve  the  burning  quality  of  peat, 
the  most  promising  of  which  appears  to  be  its  condensa- 
tion into  small  blocks.  All  the  methods  of  accomplish- 
ing this  condensation  by  pressure  seem  to  have  proved 
unsuccessful  as  to  an  increase  of  fuel  value.  It  has, 
however,  been  discovered  that  if  peat  is  made  quite  moist 
and  ground  to  a  plastic  condition  it  will  dry  in  masses 
of  considerable  hardness,  as  will  brick  clay.  Peat  thus 
ground  and  molded  into  small  blocks  so  shrinks  in 
drying  that,  when  perfectly  dry,  it  has  nearly  the  hard- 
ness of  mineral  coal.  Such  blocks  of  peat  have  been 
successfully  used  in  both  open  and  closed  grates  and 
in  stoves.  Still,  even  under  the  best  conditions,  peat 
leaves,  after  it  is  burned,  a  large  amount  of  ashes, 
mingled  with  some  earth. 


CHAPTER    V 

SOLID    FUELS  — Continued:    WOOD 
AND    CHARCOAL 

ONE  who  is  really  in  sympathy  with  nature  cannot 
view  the  felling  of  a  fine,  well-formed  tree  with- 
out almost  the  feeling  that  a  crime  has  been  committed. 
Still,  we  have  become  so  accustomed  to  those  and  similar 
acts  that  we  view  the  general  destruction  of  vegetable 
life  for  our  fuel  with  even  more  complacency  than  we 
do  that  of  animal  life  for  our  food.  Such  sacrifice  of 
other  life  for  the  preservation  and  comfort  of  our  own 
seems  to  be  a  natural  necessity,  for  it  cannot  be  doubted 
that  all  our  fuels  of  every  kind,  including  the  mineral 
coals,  have  been  derived  from  formerly,  or  now,  exist- 
ing forms  of  animal  and  vegetable  life,  respectively. 

Undoubtedly,  man's  first  fires  were  made  with  wood, 
and  it  is  even  now  in  many  respects  an  ideal  fuel.  It 
is  not  used  very  largely  in  cities,  partly  because  its  cost 
is  comparatively  greater  than  that  of  other  fuels,  and 
partly  because  it  requires  greater  space  for  storage.  It 
does,  however,  largely  supplement  the  use  of  other  fuels, 
especially  in  summer,  and  it  is  almost  indispensable  for 
kindling  coal  fires.  A  fair  knowledge  of  the  composi- 
tion and  manner  of  combustion  of  wood  adds  much  to 
one's  interest  in  a  fuel  which  is  so  convenient  and  the 
burning  of  which  gives  so  much  comfort. 

As  in  the  case  of  the  mineral  coals,  the  combustible 
37 


3  HOUSEHOLD    FUELS 

character  of  wood  depends  only  upon  the  two  fuel  ele- 
ments, carbon  and  hydrogen :  but  in  some  respects  there 
is  a  great  difference  between  these  two  general  kinds  of 
fuel.  For  example,  anthracite  and  coke  are  nearly  pure 
carbon,  and  they  give  off  no  flame  in  burning1 :  while 
wood  contains  a  liberal  proportion  of  hydrogen.  The 
latter,  together  with  a  portion  of  the  carbon,  gives  off 
an  abundance  of  ruddy  flames,  which  are  often  increased 
by  the  presence  of  resin  in  the  wood.  The  proportion 
of  carbon  is  greater  than  that  of  hydrogen  in  all  wood 
fuels,  and  woods  vary  greatly  from  one  another  with 
regard  to  those  proportions.  The  greater  the  proportion 
of  carbon  which  a  given  kind  of  wo?d  contains,  the 
greater  is  its  heating  power,  because,  although  the  hydro- 
gen flames  temporarily  give  considerable  heat,  it  is  the 
be  1  of  glowing  carbon  which  remains  after  the  flames 
have  ceased  that  gives  off  the  desired  long  and  steadv 
heat. 

Although  wood  fuel  burns  very  freely,  there  are 
some  natural  impediments  to  its  complete  combustion. 
Even  after  it  has  been  seasoned,  as  the  process  of  dry- 
ing out  of  its  natural  sap  is  generally  called,  it  so  readily 
absorbs  water  from  the  atmosphere  and  other  sources 
that  no  wood  is  entirely  free  from  moisture  unless  it  is 
kiln-dried.  \Yhen  wood  is  burned,  this  water  passes 
off  as  steam  with  other  products  of  combustion,  and 
takes  with  it.  in  a  latent  condition,  much  of  the  heat 
which  has  resulted  from  the  burning  of  the  hydrogen 
and  carbon.  \Yood.  as  well  as  many  other  fuels,  con- 
tains much  oxygen  in  its  composition,  but  it  is  believed 
that  this  oxygen  is  not  concerned  with  its  combustion. 


HOUSEHOLD    FUELS  39 

and  that  only  the  oxygen  of  the  air  is  so  concerned. 
That  is,  it  is  believed  that  not  only  does  the  oxygen 
which  enters  into  the  composition  of  wood  not  act  a-  a 
supporter  of  combustion,  but  by  uniting  with  some  of. 
its  hydrogen  forms  water,  and  so  reduce*  the  hydrogen 
combustion  of  the  fuel.  Water  formed  under  such  con- 
ditions is  already  in  the  state  of  superheated  steam,  and 
will,  as  in  the  former  case,  carry  oft"  much  latent  heat. 
This  question  of  the  chemical  production  of  water  in 
'the  process  of  combustion  of  oxygenated  fuel-  seems  to 
be  yet  an  open  one,  but  there  is  always  enough  water 
in  the  atmosphere  to  endanger  the  perfect  combustion  of 
wood  fuels.  In  every  possible  case  the  free  burning 
of  fuels  always  pays  for  keeping  them  perfectly  dry. 

Although  all  kinds  of  woody  growth  will  burn  more 
or  less  freely,  firewood,  for  obvious  reasons,  is  obtained 
from  mature  trees.  There  are  many  hundred  kind-  of 
trees  growing  in  our  country,  most  of  which  are  native 
to  the  respective  districts  where  they  grow.  The -supply 
for  the  fuel  market,  however,  is  usually  obtained  from 
a  few  of  the  kinds  of  native  trees  which  grow  in  its 
vicinitv.  Frugal  owners  of  woodlands  generally  utilize 
the  "brush."  especially  for  summer  use:  that  is.  small 
branches  of  the  trees  and  various  shrubs  which  grow 
among  them.  \Yoods  are  generally  roughly  classified  by 
dealers  as  "hard"  and  "soft."  especially  if  their  stock 
consists,  as  it  often  does,  only  of  oaks  and  hickories, 
on  the  one  hand,  and  of  pines,  on  the  other.  This  and 
other  similar  groupings  of  firewood  are  of  some  con- 
venience, but  they  do  not  give  a  desired  knowledge  of 
trees.  It  is  not  practicable  to  discuss  here  an  extended 


4O  HOUSEHOLD    FUELS 

catalogue  of  trees,  and  therefore  only  those  will  be  men- 
tioned in  the  following  paragraphs  the  wood  of  which 
is  likely  to  be  found  in  the  chief  fuel  markets  of  our 
-country. 

There  is  great  diversity  of  names  by  which  the  re- 
spective kinds  of  trees  are  known  to  the  people  of  the 
different  regions  where  they  grow.  For  this  reason  it 
is  often  difficult  to  state  a  case  clearly  when  writing 
about  wood  fuels.  The  names  for  various  kinds  of  trees 
which  are  used  by  botanists  are  intended  to  be  the  same 
everywhere.  The  same  precision  ought  to  prevail  in 
the  use  of  their  common  names,  but  unfortunately  the 
common  names  are  not  only  various  but  often  irrelevant. 

A  few  years  ago,  however,  the  United  States  Depart- 
ment of  Agriculture  made  a  strong  effort  to  secure  such 
conformity  in  the  use  of  the  common  names  of  our 
forest  trees  as  prevails  in  the  use  of  their  botanical 
names.  The  Forestry  Division  of  that  department  has 
published,  in  its  Bulletin  Number  14,  a  catalogue  of  the 
trees  of  the  United  States,  in  which  are  given  both  the 
botanical  and  common  names  of  the  species.  The  names 
of  the  few  trees  which  are  specifically  referred  to  in 
the  following  remarks  are  identical  with  names  which 
are  used  in  the  bulletin  to  which  reference  has  been 
made.  — 

Before  discussing  the  various  kinds  of  trees  which 
furnish  our  firewood,  it  is  desirable  to  state  the  charac- 
teristics of  two  great  groups  into  which  they  are 
naturally  divided,  because  the  members  of  each  group 
have  certain  fuel  characteristics  which  clearly  separate 
them  from  each  other. 


HOUSEHOLD    FUELS  41 

One  of  these  botanical  divisions  bears  the  name  of 
Angiosperms,  and  the  other,  Gymnosperms,  or  Conifers. 
Those  botanical  names  are  used  here  because  the  divisions 
which  they  represent  have  no  common  names.  The  chief 
differences  of  structure  and  foliage  between  these  two 
great  divisions  are  quite  apparent  to  every  one.  The 
angiosperms  are  well  and  typically  represented  by  the 
oaks,  with  their  acorns  and  broad,  falling  leaves ;  and 
the  pines  are  equally  typical  of  the  conifers,  with  their 
cones  and  needlelike,  evergreen  leaves.  As  will  soon 
be  shown,  the  wood  of  each  division  is  distinguished  by 
peculiarities  which  are  quite  as  striking  as  are  their 
external  characteristics. 

The  Angiosperms 

The  wood  of  the  angiosperms,  considered  as  fuel, 
differs  in  many  respects  from  that  of  the  conifers. 
Under  the  name  angiosperms  are  included  all  those 
woods  to  which  dealers  give  the  name  of  hard  wood. 
They  include  not  only  oak,  hickory,  ash,  etc.,  but  many 
comparatively  soft  woods,  as  the  soft  maples,  poplars, 
linden,  willow,  etc.  The  free  burning  of  the  wood  of 
the  angiosperms  is  due  to  their  hydrogen,  and  not  to  the 
presence  of  resin,  as  is  the  case  to  a  greater  or  less 
extent  in  all  the  coniferous  woods.  A  considerable 
amount  of  ashes  results  from  the  burning  of  the  angio- 
sperms, but  it  is  not  excessive.  The  ashes  of  the  harder 
kinds  contain  so  much  potash  that  they  were  formerly 
almost  the  only  source  of  supply  of  that  requisite  in  the 
domestic  manufacture  of  soap.  The  wood  of  the  angio- 
sperms contains  proportionately  more  carbon  than  does 


42  HOUSEHOLD    FUELS 

that  of  the  other  kinds..  They  are  therefore  more  valu- 
able as  ordinary  fuel,  and  the  charcoal  which  is  made 
from  them  is  superior  to  that  of  all  other  kinds  of  wood. 

The  angiospermous  trees  are  proportionately  more 
abundant  in  the  eastern  part  of  our  country  than  are  the 
conifers,  while  in  the  western  half  the  reverse  is  true. 
For  this  reason  the  Eastern  fuel  markets  are  more  likely 
to  be  well  supplied  with  hard  woods  than  are  the  Western 
markets. 

As  a  rule,  the  fuel  value  of  a  kind  of  wood  is  in 
proportion  to  its  density,  but  other  qualities  are  impor- 
tant, and  the  housekeeper  is  sure  to  learn  by  actual  use 
of  them  to  form  a  correct  judgment  of  the  value  of  the 
different  kinds.  For  example,  in  the  absence  of  mineral 
coal,  when  a  steady,  long-continued  heat  is  desired,  the 
hardest  woods  are  necessary,  but  for  quick,  short  fires 
in  summer  the  softer  woods  are  more  desirable.  The 
following  remarks  are  not  based  upon  systematic  tests 
to  which  different  kinds  of  wood  have  been  subjected, 
but  are  made  with  reference  to  well-known  general 
facts. 

In  the  next  following  paragraphs  mention  is  made 
of  the  principal  fuel  trees  of  our  country  in  an  order  of 
arrangement  which  is  intended  as  an  estimate  of  their 
relative  importance. 

The  hickories,  of  which  there  are  nine  known  species 
in  North  America,  are  doubtless  the  most  valuable  of 
all  our  woods  for  fuel.  Of  these  the  shellbark  and  shag- 
bark  hickories  are  superior  to  all  the  others,  but  they 
all  make  excellent  firewood.  When  hickory  wood  is 
dry  and  sound  it  burns  with  a  clear,  bright  flame,  and 


HOUSEHOLD    FUELS  43 

when  this  dies  down  there  remains  a  glowing  bed  of 
embers  which  will  last  for  a  considerable  time.  The 
supply  of  this  excellent  firewood  is  unfortunately  too 
small  in  most  regions  to  meet  household  demands. 

The  oaks  come  next  in  fuel  value,  and,  for  several 
reasons,  they  are  the  most  important  of  all.  The  fuel 
value  of  the  best  varieties  of  oak  is  nearly  equal  to  that 
of  hickory,  but  they  vary  so  greatly  that  the  fuel  value 
of  a  few  of  them  is  not  very  high.  Growing  in  this 
country  there  are  nearly  fifty  kinds  of  oak,  and  of  these 
much  the  greater  part  produce  marketable  wood.  Oak 
is  therefore  more  plentiful  than  any  other  kind  of  hard 
wood  fuel.  White  oak  is  hardly  inferior  to  the  best 
hickory,  especially  if  the  trees  from  which  it  is  obtained 
have  grown  separately  and  on  comparatively  poor  soil. 

There  are  a  few  kinds  of  oak  which  have  compara- 
tively low  fuel  value,  and  they  are  those  which  gener- 
ally grow  in  low  or  swampy  ground.  Indeed,  it  may 
be  accepted  as  a  rule  that  the  trees  of  any  given  kind 
which  have  the  greatest  fuel  value  are  those  which  grow 
alone  and  upon  upland  soil  that  is  too  poor  for  cultivated 
crops. 

The  wood  of  ash  trees  seldom  appears  in  our  fuel 
markets,  because,  although  there  are  about  a  dozen 
species  native  to  our  country,  ash  trees  are  nowhere 
abundant.  The  wood  of  all  the  species  is  similar  in 
character  to  that  of  one  another,  and  its  fuel  grade  is 
about  that  of  the  average  oak. 

Out  of  the  eight  or  nine  species  of  maple  which  are 
recognized  by  botanists  as  growing  within  the  limits  of 
the  United  States,  only  two  of  them  furnish  a  high 


44  HOUSEHOLD    FUELS 

grade  of  fuel  as  compared  with  the  oaks.  These  are  the 
sugar  maple  and  the  black  maple,  which  is  closely  related 
to  it. 

Although  birch  trees  are  comparatively  abundant  in 
some  parts  of  our  country,  they  number  only  about  half 
a  dozen  species  in  all.  The  best  of  the  birches  for  fire- 
wood is  the  black  birch,  or,  as  it  is  often  called,  the 
sweet  birch.  Children  and  others  chew  its  tender  buds 
and  bark  for  its  flavor,  which  is  similar  to  that  of 
wintergreen.  The  wood  of  the  other  birches  is  of  com- 
paratively low  grade  as  fuel. 

Sometimes  there  will  be  found  among  the  wood  as 
purchased  from  the  dealer  sticks  of  beech,  hornbeam, 
crab-apple,  dogwood,  plane  tree,  and  honey  locust 
mingled  with  the  oak  and  other  high  grade  cord  wood. 
The  quantity  of  each  of  those  kinds  of  wood  is  always 
small  and  their  quality  fairly  good,  so  their  presence  in 
the  wood  pile  is  not  greatly  objectionable.  Cotton  wood, 
and  all  the  other  poplars,  the  willow  and  linden,  all 
furnish  soft  wood  of  low  fuel  value.  The  elm,  black 
walnut,  butternut,  and  black  locust,  although  compara- 
tively dense  woods,  are  not  of  high  grade  for  fuel,  as 
they  do  not  burn  so  freely  as  do  most  trees  of  equally 
vigorous  growth.  Although  the  chestnut  is  a  strong, 
sound  wood,  it  is  objectionable  for  open  fires  because 
of  the  sparks  which  it  throws  off  when  burning. 

To  make  the  foregoing  suggestions  available  as  to 
the  relative  fuel  value  of  each  kind  of  wood,  it  is  neces- 
sary that  one  should  learn  to  recognize  each  of  the 
different  kinds  by  the  character  of  the  texture  of 
the  wood  itself,  apart  from  that  of  other  portions  of  the 


HOUSEHOLD    FUELS  45 

trees  from  which  it  comes.     Such  knowledge  is  worth 
acquiring,  and  it  is  not  difficult  to  acquire  it. 

The  Conifers 

The  conifers,  with  few  exceptions,  are  evergreens, 
and  their  winter  foliage  presents  a  strong  contrast  with 
the  leafless  condition  of  other  trees  in  winter.  The 
woody  fiber  in  all  these  trees,  especially  that  of  pines, 
is  more  or  less  permeated  with  resin,  and  the  wood  is 
more  nearly  of  uniform  grade  for  fuel,  the  proportions 
of  resin  excepted,  than  is  that  of  the  other  kinds. 
Because  of  the  presence  of  resin  these  woods  often  burn 
fiercely,  and  they  ignite  readily  because  of  their  more 
than  average  proportion  of  hydrogen  as  compared  with 
their  carbon.  This  proportion  of  hydrogen  is  so  great 
that  the  fire  is  soon  burned  out.  The  amount  of  ashes 
left  after  the  burning  of  these  woods  is  ver^  little,  and 
it  contains  almost  no  potash.  The  few  hearth  coals 
which  are  left  after  the  burning  of  any  coniferous  wood 
are  soft  and  crumbly,  and  the  charcoal  prepared  in  kilns 
from  these  woods  is  soft  and  of  low  fuel  value. 

The  kinds  of  coniferous  trees  are  numerous,  and  they 
have  a  great,  but  variable,  geographical  distribution. 
These  trees  are  much  more  abundant  in  the  Western 
half  of  our  country  than  are  any  of  the  angiosperms, 
but  in  the  interior  states  conifers  of  all  kinds  are  rare. 
In  the  following  remarks  reference  is  made  especially 
to  those  kinds  of  conifers  with  which  the  housekeepers 
of  our  country  are  most  likely  to  meet. 

There  are  nearly  or  quite  forty  native  species  of  pine 
in  our  country  recognized  by  botanists,  and  there  are 


46  HOUSEHOLD    FUELS 

few  or  no  fuel  markets  in  which  some  of  these  kinds 
are  not  represented.  They  are  all  classed  as  soft  woods 
by  dealers,  although,  on  account  of  the  resin  which  they 
contain,  they  vary  in  both  hardness  and  specific  gravity. 
Sometimes  the  differences  of  kind  are  roughly  indicated 
by  the  names,  pitch  pine,  yellow  pine,  white  pine,  etc., 
but  these  names  are  often  inappropriate.  The  pitch  pine 
regions  of  North  and  South  Carolina  and  Georgia  are 
famous  for  ponderous  timber  and  other  products  of  the 
pines.  Still,  a  large  part  of  the  pine  firewood  which 
comes  from  those  regions  to  various  city  markets  is  of 
poor  quality,  some  of  it  very  poor.  This  is  perhaps 
because  housekeepers  continue  to  purchase  such  wood. 

Occasionally  there  may  be  found  in  the  fuel  markets 
the  wood  of  spruce,  hemlock,  larch,  cypress,  cedar,  and 
juniper  (red  cedar)  mingled  with  that  of  the  pines.  To 
this  admixture  there  need  be  no  great  objection,  because 
the  fuel  value  of  those  woods  is  not  materially  less  than 
that  of  the  average  firewood  pine. 

The  towering  sequoias,  or  "big  trees,"  and  the  closely 
related,  more  abundant  redwood  trees  of  the  Pacific 
coast  regions  are  the  admiration  and  wor  ler  of  every 
one,  but  on  this  occasion  they  can  be  treated  only  as 
fuels.  The  wood  of  those  trees  is  among  the  best  of 
the  soft  wood  fuels,  being  equal  to  the  best  pine,  except 
when  a  heavily  resinous  wood  is  desired.  It  is  very 
cleanly  and  attractive  in  appearance,  being  free  from 
those  accumulations  of  pitch  which  make  the  pines  so 
unpleasant  to  handle. 

Unusual  Vegetable  Fuels.  In  cases  of  emergency 
and  irremediable  necessity,  other  vegetable  substances 


HOUSEHOLD    FUELS  47 

than  wood  have  been  used  as  fuel,  such,  for  example, 
as  the  dried  dung  of  grass-eating  animals,  compressed 
weeds,  grasses,  etc.  Here  may  also  be  mentioned  the 
occasional  use  that  has  been  made  of  Indian  corn  as  fuel. 
When  the  rich  prairie  lands  of  what  was  formerly 
known  as  our  Western  frontier  were  first  occupied,  the 
settlers  raised  abundant  crops  of  corn  every  year,  the 
market  price  of  which  was  often  very  low.  Trees  were 
scarce,  and  the  distance  from  markets  and  developed 
coal  mines  was  so  great  that  during  the  stress  of  winter 
weather  they  were  often  without  sufficient  fuel.  Their 
corncribs  were  full,  the  contents  of  which  were  an 
excellent  substitute  for  fuel ;  for  ears  of  corn  burn  as 
freely  and  give  off  quite  as  much  heat  as  does  the  best 
of  dry  wood.  One  naturally  feels  a  strong  aversion  to 
using  an  article  of  food  fcr  fuel,  but  under  the  circum- 
stances that  act  was  not  censurable,  and  the  same  settlers 
who  burned  corn  afterward  planted  and  raised  on  the 
same  farms  large  groves  of  fuel  trees.  We  are  apt  to 
forget  that  olive  oil  and  various  other  fats  which  are 
good  human  food  -have  been  used  from  time  imme- 
morial as  lighting  fuels.  It  is  not  the  purpose  here, 
however,  to  discuss  any  fuels  except  those  the  use  of 
which  is  now  prevalent  and  consistent  with  domestic 
comfort  and  convenience. 

Charcoal.  When  flame  accompanies  combustion  of 
carbon  in  the  household  use  of  solid  fuels,  if  not  accom- 
panied by  smoke,  it  is  not  only  not  objectionable,  but 
often  specially  agreeable.  In  household  work,  however, 
it  is  often  necessary  to  have  a  glowing  fire,  free  from 
flame  and  smoke.  When  it  is  desired  to  have  a  long- 


48  HOUSEHOLD    FUELS 

continued  fire  of  this  kind,  anthracite  is  the  best  fuel 
that  can  be  used  for  the  purpose.  Both  coke  and  char- 
coal, however,  are  ideal  flameless  fuels,  both  of  them 
consisting  of  almost  pure  carbon,  and  both  burn  freely 
and  steadily. 

Charcoal  bears  the  same  relation  to  wood  that  coke 
bears  to  bituminous  coal,  which  has  already  been  dis- 
cussed. Charcoal  is  wood  which  has  been  freed  from 
its  hydrogen  and  other  volatile  contents  by  heat.  The 
crumbling  hearth  coals  which  remain  after  a  wood  fire 
are  also  charcoal,  but  that  which  is  found  in  the  fuel 
markets  has  been  produced  in  kilns  specially  constructed 
for  that  purpose.  From  the  most  complete  of  these 
kilns  we  obtain  not  only  the  best  quality  of  charcoal, 
but  also  many  valuable  by-products.  Among  these  is 
wood  alcohol,  which  will  be  given  appropriate  mention 
among  the  liquid  fuels. 

The  modern  kiln,  often  called  the  beehive  kiln 
because  of  its  dome  or  approximately  hemispherical 
shape,  is  substantially  built  of  brick.  An  opening  is 
made  at  the  apex  through  which  the  wood  is  introduced, 
and  which  also  serves  temporarily  as  a  draft  exit.  At 
the  base  are  openings  to  admit  air  to  the  kindling  fire 
within,  and  also  a  larger  opening  for  the  removal  of 
the  charcoal.  Covers  are  provided  for  each  of  these 
apertures,  so  that  they  may  be  instantly  closed  when 
necessary.  When  the  process  is  completed  and  the  kiln 
is  cooled,  all  the  products  are  available,  but  it  is  only 
the  charcoal  and  the  wood  alcohol  with  which  we  are 
now  concerned. 

Charcoal  made  in  a  kiln  of  this  kind  from  good  hard 


HOUSEHOLD    FUELS  49 

wood  is  a  most  satisfactory  fuel  for  special  purposes, 
and  it  is  ready  for  immediate  use  as  it  comes  from  the 
kiln.  The  wood  alcohol,  however,  must  undergo  a 
somewhat  elaborate  process  of  separation  from  the  other 
by-products  before  it  can  be  used  as  a  household  fuel. 
The  fine  quality  of  charcoal  made  in  these  kilns  breaks 
with  a  clean  fracture,  which  is  independent  of  the  grain 
of  the  wood,  and  when  the  pieces  are  shaken  together 
in  the  fuel  basket  they  give  forth  a  faint  metallic  tinkle. 
Charcoal  made  of  soft  wood  does  not  possess  these 
characteristics,  and  it  is  dirty  to  handle  and  burns  out 
more  quickly. 

Formerly,  rude  charcoal  kilns  were  made  in  the 
forests  by  woodmen,  and  such  are  now  occasionally 
made  to  supply  local  demands.  The  wood  is  cut  in  pieces 
a  foot  or  two  in  length  and  stacked  on  end  in  a  dome- 
shaped  pile  on  the  ground.  The  pile  is  then  covered 
with  sod  and  earth,  openings  being  left  at  the  top  and 
base  similar  to  those  in  the  kilns  built  of  brick,  which 
have  just  been  described.  The  fire  is  applied  within 
the  openings  at  the  base,  and  when  the  mass  of  wood 
within  is  burning  well  these  apertures  are  gradually 
closed,  but  the  fire  within  the  kiln  does  not  become  com- 
pletely extinguished  until  the  charring  is  complete.  The 
hydrogen  and  all  other  volatile  products  pass  off  through 
the  summit  aperture,  no  effort  being  made  by  the  wood- 
men to  save  them.  The  ^charcoal  only  remains,  and  is 
obtained  by  removing  the  sods  and  destroying  the  kiln. 
Charcoal  made  in  this  rude  way  is  sometimes  good,  but 
it  does  not  generally  make  a  very  satisfactory  household 
fuel  because  of  the  frequent  presence  in  it  of  uncharred 
pieces  of  wood  and  dirt  from  the  kiln  covering. 


5O  HOUSEHOLD    FUELS 

Tar  and  Resin-.  The  woodmen  of  some  of  the 
Southern  pine  forests  frequently  construct  kilns,  not  for 
the  production  of  charcoal,  but  tar,  the  substance  which 
is  proverbially  associated  with  the  life  of  the  sailor. 
Tar  is  not  a  fuel,  but  the  method  of  its  production  is 
mentioned  here  because  it  is  an  inversion  of  the  method 
of  charcoal  production  and  a  destructive  one  of  wood 
distillation. 

The  tar  kiln  is  a  hole  of  inverted  conical  shape,  dug 
in  the  earth  at  the  brow  of  an  abruptly  sloping  bank,, 
so  that  it  may  be  easily  drained  out  upon  the  lower 
ground  surface.  '  It  is  six  or  eight  feet  in  diameter  at 
the  top,  but  only  a  foot  and  a  half  at  the  bottom,  where 
an  iron  pan  is  fitted  which  has  a  drainage  spout.  The 
kiln  is  filled  with  short  pieces  of  pitchy  pine  and  fired 
at  the  top.  The  fire  burns  downward,  causing  the  resin 
to  ooze  from  the  wood  and  mingle  with  the  other 
products  of  wood  distillation.  The  mixture  is  tar,  and 
it  gathers  in  the  pan  at  the  bottom  of  the  kiln  and  passes 
out  by  its  spout  to  the  receptacle. 

Pure  resin  is  produced  from  pine  trees  similar  to 
those  which  produce  tar,  but  it  is  obtained  in  quite  a 
different  manner.  Wounds  are  made  in  the  trunks  of 
living  trees,  and  from  these  the  viscid  pitch  exudes, 
which  consists  of  resin  and  oil  of  turpentine.  The  pitch 
is  distilled  in  water,  that  it  may  not  be  scorched ;  the 
volatile  oil  of  turpentine  passes  off  and  is  secured.  The 
remainder  is  commercial  resin. 


CHAPTER    VI 
THE    SEMI-SOLID    FUELS 

'  I  VHE  solid  fuels  are  used  only  as  hetit  producers; 
•*•  even  the  .flame,  which  accompanies  the  combustion 
of  some  of  them,  is  utilized  for  heat  and  not  for  light. 
The  semi-solid  fuels,  on  the  other  hand,  are  adapted  to 
the  production  of  light  only.  These  fuels  are  completely 
consumed  in  combustion,  and,  if  pure,  they  leave  no 
residue  of  any  kind.  Some  of  them  are  still  used  in  the 
household  for  convenience,  but  their  use  has  been  greatly 
lessened  by  the  introduction  of  the  mineral  oils.  Only 
those  which  are,  or  have  been,  much  used  in  the  house- 
holds of  our  country  are  mentioned  in  the  following 
paragraphs.  These  fuels  vary  in  consistency  from  that 
of  lard  to  that  of  beeswax  and  resin.  All  of  them  melt 
at  comparatively  low  heat  and  return  unchanged  to  their 
original  semi-solid  condition  on  cooling. 

The  semi-solid  fuels  which  have  been  selected  for 
mention  are  fat,  wax,  stearin,  palmitin,  spermaceti,  and 
paraffin ;  and  to  these  resin  is  added  because  of  its  con- 
nection with  the  origin  of  oil  of  turpentine,  one  of  the 
liquid  fuels.  The  five  first  named  semi-solid  fuels  are 
sometimes  spoken  of  as  oxygenated  hydrocarbons,  be- 
cause they  consist  not  only  of  hydrogen  and  carbon, 
but  also  contain  a  proportion  of  oxygen.  Although  the 
sixth  kind,  paraffin,  resembles  spermaceti,  stearin,  and 
palmitin  in  appearance,  it  is  a  pure  hydrocarbon,  being 
composed  of  hydrogen  and  carbon  only. 

51 


52  HOUSEHOLD    FUELS 

Fats.  Generally,  one  is  apt  to  think  of  fats  as  animal 
substances  rather  than  as  vegetable  products.  It  is  true 
that  many  of  the  fats  used  in  the  household  are  animal 
fats,  but  true  fats  are  furnished  by  the  nutlike  fruits  of 
many  and  widely  different  kinds  of  plants.  Some  of  not 
only  the  animal,  but  of  the  vegetable  fats  consist  of  two 
parts,  both  of  which  are  combustible  without  residue. 
As  the  fat  is  seen  under  ordinary  observation,  these  parts 
are  apparently  inseparable,  but  methods  for  separating 
them  completely  have  long  been  in  use.  One  of  the  parts 
is  an  oil  and  the  other  is  a  semi-solid,  such  as  are  now 
under  discussion.  The  proportion  of  these  two  parts 
differs  considerably  in  the  fat  of  different  animals ;  for 
example,  that  of  the  ox  differs  greatly  from  that  of  the 
hog.  The  proportion  also  differs  considerably  in  the  fat 
of  individual  animals  of  the  same  kind,  according  to  the 
food  with  which  they  have  been  fed. 

It  is  a  fact  well  known  to  thrifty  farmers  that  the 
fat  of  corn- fed  hogs  is  much  firmer  than  is  that  of  those 
which  are  either  swill- fed  or  mast- fed.  The  lard  made 
from  the  fat  of  mast-fed  hogs  is  sometimes  so  soft  that 
it  becomes  liquid  with  summer  heat  of  the  atmosphere. 
On  the  contrary,  the  kidney  fat  of  the  ox  and  sheep  is 
almost  of  waxy  hardness  after  it  has  been  freed  from 
its  animal  tissue  by  melting,  because  the  oily  part  of  the 
fat  is  only  slightly  represented. 

There  is  now  no  occasion  for  the  use  of  any  of  the 
fats  as  household  fuels  without  separating  their  oily  from 
their  semi-solid  portions,  but  formerly  lard  was  occasion- 
ally and  tallow  very  extensively  so  used.  A  brief  descrip- 
tion of  the  manner  of  using' those  two  fuels  for  lighting 


HOUSEHOLD    FUELS  53 

purposes  will  be  of  interest,  because  it  will  show  how 
important  certain  articles  formerly  were  in  the  household 
that  would  not  now  be  tolerated. 

Lard  Lamps.  In  the  early  part  of  the  nineteenth 
century  tallow  was  constantly  used  for  candles  through- 
out the  whole  breadth  of  our  country,  but  upon  what 
was  then  our  Western  frontier  lard  was  frequently 
burned  in  lamps  just  as  it  came  from  the  rendering 
kettles.  This  use  of  lard  for  lighting  fuel  was  mainly 
confined  to  the  region  referred  to,  because  hog  products' 
were  abundant  and  cheap  there ;  but  the  practice  was  not 
prevalent  elsewhere,  and  it  did  not  last  many  years. 
This  use  of  lard  is  mentioned  here  to  show  one  of  the 
various  expedients  to  which  our  people  resorted  to 
obtain  household  light.  The  lamps  so  used  were  much 
like  those  in  which  whale  oil  was  burned,  but  because 
it  was  necessary  to  have  the  lard  in  an  oily  condition 
before  it  would  rise  in  the  wick  it  was  melted  in  another 
vessel  and  poured  into  the  lamp.  Sometimes,  to  avoid 
this  extra  labor,  a  narrow  strip  of  copper  was  attached 
to  the  side  of  the  wick  tube,  reaching  from  the  lard  to 
the  top  of  the  wick.  Sometimes  the  whole  wick  tube 
was  made  of  copper,  but  as  it  soon  collected  verdigris, 
that  use  of  it  was  objectionable.  Copper  is  such  a  good 
conductor  of  heat  that  it  soon  melted  enough  of  the 
lard  to  start  an  upward  flow  in  the  wick  when  a 
flame  was  held  a  short  time  to  its  upper  end.  In  this 
way  the  lamp  was  lighted  and  gave  what  was  then  ah 
acceptable  flame. 

Tallow  Candles.  At  the  time  referred  to  in  the  last 
paragraph,  the  use  of  the  tallow  candle  was  universal, 


54  HOUSEHOLD    FUELS 

and  the  preparation  of  the  candles  and  of  the  tallow  to 
make  them  was  one  of  the  important  labors  of  the  house- 
hold. Indeed,  the  use  of  such  candles  was  to  our 
ancestors  an  ancient  custom,  and  they  evidently  accepted 
its  inconveniences  as  inevitable. 

Among  our  people,  rendered  tallow  was  a  common 
article  of  merchandise  at  the  village  stores,  and  the 
butcher  sold  his  candle  tallow  with  his  meats,  in  which 
case  the  rendering  of  it  was  added  to  the  labor  of  the 
housekeeper.  The  candles  which  she  made  were  either 
molded  or  dipped,  the  latter  process  being  the  more 
ancient  household  art. 

For  dipping  candles,  a  deep  iron  kettle  was  placed 
over  a  fire,  partly  filled  with  water.  When  the  water 
boiled,  enough  rendered  tallow  was  put  into  the  kettle 
to  bring  its  melted  surface  near  the  top.  The  tallow, 
of  course,  floated  upon  the  water.  The  candle  wick- 
ing,  which  consisted  of  loosely  twisted  cotton  threads, 
was  cut  into  lengths  double  the  length  of  the  candles  to 
be  made.  These  wicks  were  folded  over  a  slender  rod 
of  wood  and  the  two  parts  slightly  twisted  together. 
About  half  a  dozen  of  these  wicks  were  suspended  from 
each  of  the  rods,  each  wick  being  little  less  than  a  quarter 
of  an  inch  in  diameter.  The  wicks,  dangling  from  the 
rods,  were  dipped  into  the  melted  tallow,  the  upper  ends 
being  held  above  its  surface  by  the  rods,  which  extended 
across  the  kettle.  The  dipped  wicks  were  immediately 
hung  upon  a  frame  to  cool,  and  were  straightened  with 
the  fingers.  When  cooled,  the  incipient  candles  were 
dipped  and  quickly  removed  again  and  again  until  they 
were  of  the  desired  thickness.  These  candles  were  much 


HOUSEHOLD    FUELS  55 

like  the  candles  of  today,  but  they  were  exceedingly  crude 
and  unsightly  objects. 

The  molding  of  candles  did  not  find  its  way  into 
American  households  until  after  the  first  third  of  the 
last  century.  Previous  to  that  time  it  had  been  practiced 
as  a  chandler's  art,  and  the  candles  so  made  were  used 
in  churches  and  public  places.  The  candle  molds  which 
were  first  introduced  for  household  use  were  made  of 
sheet  tin,  and  soon  became  an  article  of  merchandise, 
together  with  other  tinware.  They  were  cylindrical 
tubes,  usually  made  in  groups  of  three,  four,  or  six,  and 
slightly  larger  at  one  end  than  the  other.  There  was  a 
conical-shaped  cover,  with  a  hole  in  its  apex,  through 
which  the  wick  was  passed,  which  closed  the  smaller  end 
of  each  mold.  At  the  larger  and  open  end  the  wick  was 
held  in  place  by  a  small,  transverse,  wooden  rod.  The 
melted  tallow  was  poured  into  the  larger  end,  filling 
each  of  the  tubes.  As  tallow  shrinks  slightly  on  cooling, 
the  candles  were  easily  withdrawn. 

The  same  large  wicks  were  used  for  these  candles 
that  were  used  for  those  that  were  dipped.  Such  wicks 
were  only  charred,  not  consumed,  as  the  candle  burned 
down,  and  the  light  was  thereby  much  diminished.  It 
was  therefore  frequently  necessary  to  remove  the  charred 
wick  with  snuffers,  which  were  kept  constantly  at  hand. 
The  small  braided  wicks  which  are  now  used  in  candles 
were  not  then  known.  These  small  wicks  turn  aside 
to  the  air  as  the  candle  shortens,  and  the  end  is  there 
consumed  to  ashes  and  needs  no  snuffing. 

Wax.  The  known  varieties  of  wax  are  not  only 
numerous  but  diverse,  some  of  them  being  of  animal 


56  HOUSEHOLD    FUELS 

and  others  of  vegetable  origin.  There  are  also  some 
mineral  substances  which  are  waxlike.  Only  two  of  the 
substances  which  are  called  wax  need  to  be  mentioned 
here,  as  most  of  those  so-called  have  no  place  among 
household  fuels.  These  two  are  beeswax  and  the  wax 
which  is  obtained  from  the  bayberry  shrub,  or  wax 
myrtle.  Indeed,  the  practical  use  of  both  of  these  sub- 
stances as  accessory  light  fuels  long  ago  passed  away. 

Crude  beeswax  is  only  melted  honeycomb,  and  was 
used  in  that  condition  to  harden  tallow  candles  for 
summer  use.  When  beeswax  is  refined  and  bleached  it 
is  of  nearly  pure  white  color,  and  was  formerly  much 
used  upon  religious  and  other  important  occasions,  but 
it  seldom  made  its  appearance  in  the  household  in  that 
refined  condition. 

Myrtle  wax  is  formed  as  a  slight  grayish  film  on  the 
outside  of  the  small,  spherical,  seed-like  fruits  which  grow 
in  clusters  on  the  bayberry  shrub.  This  shrub  is  found 
growing  on  open  waste  grounds  of  the  Atlantic  coast 
region,  from  Nova  Scotia  to  Florida.  The  fruit  is  placed 
in  large  kettles  nearly  filled  with  water,  which  is  boiled 
until  the  wax  floats  upon  the  surface.  The  refuse  is 
removed,  and  when  the  water  cools  the  wax  forms  as 
a  crust  upon  its  surface.  Sometimes  candles  have  been 
formed  of  this  wax  alone,  but  its  former  domestic  use 
was  only  to  harden  tallow  candles.  Because  this  wax  was 
never  abundant,  it  was  never  extensively  used. 

Impurities,  or  small  bits  of  any  kind  which  were  left 
in  the  tallow  when  it  was  rendered,  or  in  either  of  the 
two  kinds  of  wax  when  added  to  the  tallow,  made  the 
candles  "gutter,"  and  thus  increased  their  inefficiency 


HOUSEHOLD    FUELS  57 

and  ugliness.  When  no  wax  was  obtainable,  alum  was 
sometimes  added  to  the  tallow  to  harden  it,  but  as  alum 
interfered  with  the  burning  of  the  candle  and  lessened 
the  amount  of  its  light,  that  method  of  hardening  was 
seldom  used. 

Stearin.  Chemists  know  this  substance  as  stearic 
acid,  but  the  commercial  name  is  stearin,  and  that  name 
is  generally  used  in  the  household.  Stearin  is  found  in 
animal  fats,  and  some  chemists  recognize  the  correspond- 
ing semi-solid  of  vegetable  fats  also  as  stearin,  and  not 
always  as  palmitin.  It  is  separated  from  its  oily  associate 
by  a  process  which  leaves  the  latter  in  a  permanently 
liquid  condition.  It  was  the  stearin  of  the  fat  of  hogs 
and  other  domestic  animals  that  first  caused  the  retire- 
ment of  the  tallow  candle.  The  common  candle  now  in 
use,  however,  is  usually  made  of  paraffin,  stiffened  with 
beef  stearin. 

Palmitin.  This  substance  bears  the  same  relation 
to  the  fats  of  certain  kinds  of  palms  and  other  trees 
that  stearin  does  to  the  animal  fats.  The  semi-solid  part 
of  that  vegetable  fat  is  known  as  palmitin,  but  it  is  so 
closely  like  stearin  in  appearance  and  use  that  the  house- 
keeper will  generally  not  care  to  distinguish  them  apart. 
Its  associated  oil  is  palm  oil,  which  is  much  more  used 
in  the  industrial  arts  than  in  the  household. 

Spermaceti.  Few  substances  of  its  kind  have  been 
longer  or  more  favorably  known  than  spermaceti.  It 
is  the  semi-solid  part  of  the  fat  obtained  from  the  whale, 
mostly  the  sperm  whale,  and  bears  the  same  relation  to 
their  fat  that  stearin  does  to  other  animal  fats.  The  best 
spermaceti  is  obtained  from  the  oily  fat  which  is  found 


5  HOUSEHOLD    FUELS 

in  certain  parts  of  the  head  of  the  sperm  whale.  It  is 
among  the  most  beautiful  and  satisfactory  of  all  the 
substances  which  have  been  used  for  making  candles. 
When  thoroughly  purified,  its  slightly  translucent  white- 
ness makes  a  candle  of  this  substance  a  pleasing  and 
striking  object.  It  is  still  occasionally  used  to  make 
candles  for  the  use  of  those  whose  aesthetic  tastes  prefer 
its  slender  flame  to  the  brilliant  glare  of  those  illuminants 
which  have  driven  the  candle  from  common  use  except 
as  a  small  portable  light. 

Paraffin.  This  name  has  been  used  to  denote  various 
substances,  but  by  the  term  as  here  used  is  meant  the 
waxy,  white,  translucent  mineral  product  which  is  gener- 
ally recognized  by  that  name  in  our  country.  Sometimes 
it  is  found  more  or  less  pure  in  the  earth,  but  most  of 
that  which  is  sold  in  the  markets  is  obtained  from  petro- 
leum, and  is  now  abundant.  In  former  years  it  was 
obtained  in  comparatively  small  quantities  from  certain 
kinds  of  mineral  coal,  and  even  from  peat. 

Paraffin  is  used  for  various  purposes,  but  its  use  as 
a  household  fuel  is  only  in  the  form  of  candles.  Such 
candles  burn  with  a  good  flame,  and  the  best  of  them 
are  sometimes  sold  for  wax  or  spermaceti.  Candles 
made  from  paraffin  alone  have  a  good  appearance,  but 
they  become  so  softened  by  summer  heat  that  they  often 
bend  over  and  lose  their  shape.  It  is  for  this  reason  that 
the  candles  which  are  sold  in  the  markets  consist  largely 
of  paraffin  stiffened  with  beef  stearin. 

Resin.  The  name  resin  is  applied  to  many  different 
substances  in  medicine  and  the  arts.  As  found  in  the 
markets,  the  -substance  here  referred  to  is  in  brown, 


HOUSEHOLD    FUELS  59 

brittle,  translucent  lumps,  which  break  with  clean  but 
irregular  fractures.  Although  it  melts  at  comparatively 
low  temperature,  it  returns  to  its  original  condition  on 
cooling.  When  it  exudes  from  wounds  which  are  made 
through  the  bark  of  pitch  pine  trees  it  has  about  the  con- 
sistence of  honey,  but  it  acquires  a  brittle  hardness  after 
long  exposure  to  the  air,  or  after  it  has  been  artificially 
freed  from  its  oil  of  turpentine.  Its  only  place  among 
the  household  fuels  of  the  present  day  is  its  occasional 
application  to  the  ends  of  kindling  wood,  that  they. may 
ignite  more  readily.  It  was  formerly  used  in  the  making 
of  links,  or  torches,  to  light  the  entrances  to  large  dwell- 
ings, especially  upon  gala  occasions.  The  manner  of 
preparing  resin  for  the  market  has  already  been  men- 
tioned in  connection  with  that  of  producing  tar  from 
the  wood  of  pine  trees. 


CHAPTER   VII 
THE    LIQUID    FUELS 

TT  has  been  shown  that  the  semi-solid  fuels  produce 
*•  flame  with  comparatively  little  heat,  and  that  they 
leave  no  residue  of  any  kind.  We  are  now  to  see  that 
this  is  precisely  the  case  with  all  liquid  and  gaseous  fuels, 
and  that  these  three  kinds  form  a  section  which  is  quite 
different  from  the  section  formed  by  the  solid  fuels. 

Every  liquid  fuel  is  ready  at  all  times  to  pass  up 
through  the  lamp  wick,  or  a  piece  of  asbestos  in  some 
cases,  by  capillary  action,  there  to  be  quickly  changed 
to  a  gaseous  condition  and  completely  burned.  All  the 
semi-solid  fuels  are  used  in  the  household  only  in  the 
form  of  candles,  and  the  manner  of  their  combustion 
may  be  conveniently  observed.  When  the  wick  is  lighted 
the  substance  of  the  candle  is  melted  by  its  heat  to 
the  condition  of  oil.  This  newly  formed  oil  passes  up 
through  the  candle  wick  just  as  ordinary  oil  does  in  the 
lamp  wick.  Thus  all  the  semi-solid  fuels  are  reduced 
to  a  liquid,  and  from  a  liquid  to  a  gaseous  condition 
before  they  are  burned,  and,  like  the  gaseous  fuels,  they 
leave  no  residue  after  burning.  These  facts  show  that 
the  semi-solid  fuels  are  really  only  congealed  liquid  fuels 
so  far  as  the  production  of  flame  is  concerned,  their 
difference  of  condition  being  only  one  of  temperature. 
Pursuing  that  idea  still  farther,  we  shall  see  that  the 
liquid  fuels  and  the  liquefied  semi-solid  fuels  are  only 

60 


HOUSEHOLD    FUELS  6l 

condensed  gases,  the  difference  in  each  case  of  practical 
use  being  only  that  of  temperature. 

The  liquid  fuels  may  be  divided  into  two  general 
classes,  oils  and  alcohols.  There  are  several  groups  of 
oils  and  many  kinds  in  each  group,  but  kinds  belonging 
to  only  two  of  the  groups  have  been  used  as  household 
lighting  fuels.  These  are,  first,  the  true  oils,  sometimes 
called  the  organic  oils,  or  fats  of  either  animal  or  vege- 
table origin ;  and  second,  the  mineral  oils,  which  are  true 
hydrocarbons,  although  the  term  oil  has  become  insepa- 
rably connected  with  them.  Because  the  true  oils  contain 
oxygen  besides  carbon  and  hydrogen,  they  are  sometimes 
called  oxygenated  hydrocarbons.  Some  of  these  oils  of 
both  animal  and  vegetable  origin  may  be  used  as  liquid 
fuels  just  as  they  were  obtained  from  their  respective 
sources,  but  others  of  each  kind  must  be  separated  from 
a  semi-solid  substance  with  which  they  are  associated  in 
their  origin  before  they  can  be  so  used.  The  two  oils 
which  are  mentioned  in  the  next  paragraph  illustrate  the 
conditions  referred  to. 

Olive  and  Palm  Oils.  These  two  oils  not  only 
serve  to  show  the  relation  of  vegetable  oils  to  one 
another,  but  also  the  relation  of  a  part  of  them  to  the 
semi-solid  fuels.  These  examples  also  show  the  similarity 
of  animal  and  vegetable  oils  as  fuels.  Both  olive  and 
palm  oil  are  among  the  oldest  known  oils  used  as  light- 
ing fuels,  but  neither  of  them  has  ever  been  practically 
used  for  that  purpose  in  American  households.  In  its 
crude  state  palm  oil  is  associated  with  the  well-defined 
semi-solid  substance,  palmitin,  but  olive  oil  is  nearly  free 
from  such  an  associate.  The  flocculence  which  is  seen 


62  HOUSEHOLD    FUELS 

in  even  the  purest  olive  oil  in  very  cold  weather  is  due 
to  the  presence  of  a  small  quantity  of  stearin,  but  that 
flocculence  quickly  disappears  by  the  liquefaction  of  the 
stearin  as  the  temperature  rises.  Olive  oil  has  been  used 
from  time  immemorial,  and  its  religious  as  well  as  its 
secular  associations  make  one  almost  feel  a  veneration 
for  it.  We  have  every  reason  to  believe  that  it  was  the 
first  oil  that  was  used  to  light  human  dwellings. 

Whale  Oil  and  Lard  Oil.  Lard  oil  is  one  of  those 
animal  oils  to  which  reference  has  been  made  as  being 
organically  associated  with  stearin  in  fats  in  large  and 
easily  obtainable  quantity.  This  oil  is  now  mentioned 
only  to  compare  it  with  whale  oils,  which  are  almost 
free  from  stearin  as  they  are  originally  obtained.  The 
mention  of  lard  oil  again  is  not  for  its  importance,  but 
for  the  purpose  of  referring  to  the  historical  fact  of  its 
brief  domestic  use  as  a  household  lighting  fuel  before 
the  discovery  of  petroleum  by  deep  boring  in  the  earth, 
which  occurred  in  1859.  That  discovery  was  made  when 
lard  oil  was  used  in  those  parts  of  our  country  where 
hog  products  were  cheap  enough  to  compete  with  whale 
oil.  That  competition,  however,  was  of  limited  extent 
and  short  duration,  and  it  was  ended  by  the  introduction 
of  mineral  oils  to  the  household,  which  also  ended  the 
use  of  whale  oil  in  household  lamps. 

Up  to  the  time  of  that  discovery  of  petroleum  in 
Pennsylvania,  whale  oil  was  the  most  serviceable  light- 
ing fuel  then  to  be  obtained  in  our  country,  and  was 
more  generally  used  than  any  other  except  the  tallow 
candle.  The  oil  of  the  Greenland  whale  was  the  kind 
then  commonly  used,  but  that  of  the  sperm  whale  was 


HOUSEHOLD    FUELS  63 

the  best  and  also  the  most  expensive  lamp  oil  then  in  use 
among  our  people.  Those  oils  were  generally  used  just 
as  they  came  from  the  rendering  kettles  of  the  sailors, 
who  also  carried  on  a  sort  of  rude  chandlery  on  ship- 
board for  separating  the  spermaceti  from  its  associated 
sperm  oil. 

Before  the  great  discovery  of  petroleum  in  Pennsyl- 
vania, fishing  on  the  high  seas  for  whales  from  which 
to  obtain  oil  was  among  the  great  business  enterprises 
of  that  time.  For  many  years  good  catches  of  whales, 
grampuses,  porpoises,  and  seals  were  made  upon  com- 
paratively short  voyages  by  the  crews  of  the  smaller 
vessels,  but  the  great  whaling  enterprises  were  prose- 
cuted by  means  of  well-manned  ships  which  sailed  from 
New  Bedford  and  Nantucket  as  far  as  Bering  Sea,  by 
way  of  Cape  Horn.  The  average  time  required  for  the 
round  voyage  of  each  vessel  was  about  four  years. 
Notwithstanding  such  length  of  the  cruises,  there  were 
so  many  of  the  vessels  sailing  from  those  two  ports  alone 
that  their  general  sailing  course  was  a  great  marine 
highway.  The  large  amount  of  oil  which  was  then 
taken  by  those  ships  found  its  way  into  almost  every 
home  in  our  country,  until  its  use  was  brought  suddenly 
to  an  end  by  the  flooding  of  the  markets  with  mineral 
oil.  It  is  thought  well  to  repeat  this  reference  to  that 
fact  because  it  relates  to  one  of  the  most  sudden  revo- 
lutions that  have  occurred  in  domestic  usage. 

At  the  present  day  our  households  are  so  easily  and 
brilliantly  lighted  that  it  is  difficult  to  understand  how 
the  housekeepers  of  those  early  days  accomplished  any 
work  in  a  suitable  manner  during  the  long  evenings,  with 


64  HOUSEHOLD   FUELS 

their  poor  and  inefficient  lights.  The  lamps  which  were 
used  for  whale  and  other  oils  were  usually  made  of 
japanned  tin,  and  held  less  than  half  a  pint  of  oil.  The 
flame  of  those  lamps  was  clearer  than  that  of  the  tallow 
candles,  but  little  if  any  larger.  The  lamps  were  as 
uncleanly  as  the  candles,  if  not  more  so,  for  oil  constantly 
escaped  from  the  screw-joint  of  the  wick  tube  and  spread 
as  a  film  over  the  whole  outer  surface  of  the  lamp,  so 
that  it  required  frequent  wiping.  Every  housekeeper 
can  see  how  almost  impossible  it  would  be  to  keep  delicate 
goods  from  becoming  soiled  by  such  lamps. 

When  we  consider  the  inefficiency  and  inconvenience 
of  the  only  household,  lighting  fuels  that  were  available 
in  those  early  days,  we  do  not  wonder  that  our  people 
were  constantly  looking  for  something  better.  It  was 
of  such  necessities  that  our  present  splendid  system  of 
household  illumination  was  born.  The  trials  which  our 
frugal  people  gave  to  various  products,  as  already  men- 
tioned, showed  their  habit  of  inquiry,  which  is  still 
further  indicated  in  the  next  paragraph. 

Oil  of  Turpentine.  This  oil,  being  very  combusti- 
ble, was  thought  by  a  few  persons  to  promise  well  as  an 
illuminant,  and  it  was  so  used  to  some  extent  before  the 
general  introduction  of  mineral  oils.  Alcohol  was  mixed 
with  it  and  the  mixture  sold  under  the  name  of  "cam- 
phene,"  or  burning  fluid.  The  lamps  in  which  it  was 
burned  were  similar  in  size  and  shape  to  those  used  for 
whale  oil,  but  each  had  a  slender  wick  tube,  which  was 
provided  with  a  small  metal  cap  to  extinguish  the  flame. 
This  fluid  mixture  proved  to  be  explosive  and  therefore 
exceedingly  dangerous  in  the  household.  Its  use  was  at 


HOUSEHOLD    FUELS  65 

best  only  an  experiment,  and  it  soon  went  out  of  use.  Its 
brief  mention  here  is  only  to  show  how  earnestly  the 
people  were  groping  for  better  light,  and  how  often  they 
failed. 

Oil  of  turpentine  is  a  true  oil  of  the  -volatile  group, 
but  it  is  commonly  known  as  spirit  of  turpentine ;  and 
house  painters,  who  use  great  quantities  of  it,  usually 
shorten  the  name  to  "turpentine."  Like  all  true  oils, 
it  contains  oxygen  in  addition  to  hydrogen  and  carbon, 
but  unlike  those  oils  it  is  volatile. 

Mineral  Oils.  The  lighter  grades  of  mineral  oil  are 
quite  as  volatile  as  the  oil  of  turpentine,  but  they  are  all 
true  hydrocarbons,  being  composed  of  hydrogen  and 
carbon  only.  The  mineral  oils  have  become  so  impor- 
tant, not  only  in  the  household  but  in  the  industrial 
world,  that  facts  relating  to  their  discovery  in  large 
quantity,  and  to  the  character  of  the  crude  oil  and  its 
refined  products,  are  of  unusual  interest.  The  crude  oils 
are  obtained  from  two  sources.  One  of  them,  which  is 
called  petroleum,  is  obtained  directly  from  the  earth  by 
borings  like  those  of  artesian  wells ;  the  other,  commonly 
called  coal  oil,  is  obtained  by  distillation  of  certain  kinds 
of  mineral  coal  or  of  bituminous  earth,  or  shale.  Crude 
coal  oil  and  petroleum  are  practically  identical  in  com- 
position and  character.  Both  have  a  varying  brownish 
color,  and  both  also  vary  in  density  according  to  the 
proportions  of  the  refined  products  which  may  be 
obtained  from  them. 

Refiners  have  recognized  not  less  than  seven  grades 
of  refined  oils  from  petroleum  besides  the  semi-solid 
products,  paraffin  and  vaseline,  all  of  which  are  pure 


66  HOUSEHOLD    FUELS 

hydrocarbons.  All  grades  of  the  refined  oils  mix  readily 
with  one  another  in  all  proportions  and  at  all  temper- 
atures of  the  atmosphere.  The  following  names  have, 
at  various  times,  been  applied  to  those  grades,  beginning 
with  the  lightest :  cymogene,  rhigolene,  gasoline,  naphtha, 
benzine,  kerosene,  headlight  oil,  and  lubricating  oil. 
Refiners  generally  now  retain  only  the  following  names : 
lubricating  oil,  which  is  the  densest  grade  and  is  used 
for  lubricating  heavy  machinery ;  headlight  oil,  which  is 
used  for  headlight  lamps  of  locomotive  engines ;  kero- 
sene, the  commonest  of  household  heating  and  lighting 
liquid  fuels ;  and  gasoline,  sometimes  used  in  the  house- 
hold for  fuel,  but  more  often  used  in  the  industrial  arts 
and  for  motor  engines  of  various  kinds. 

All  the  other  names  for  the  successive  grades  of  oil 
lighter  than  kerosene  have  been  abandoned  by  most 
refiners  and  dealers,  each  grade  having  received  the 
name  gasoline  with  the  addition  of  a  number.  That  is, 
benzine  is  gasoline  i  ;  naphtha  is  gasoline  2 ;  gasoline 
is  gasoline  3  ;  rhigolene  is  gasoline  4 ;  and  cymogene  is 
gasoline  5.  All  these  lighter  grades  of  mineral  oils,  as 
well  as  carefully  tested  kerosene,  are,  to  the  casual 
observer,  simply  transparent  liquids,  having  the  same 
general  aspect  and  all  readily  and  permanently  mixing 
together.  They  also  all  contain  the  same  two  chemical 
elements,  namely,  carbon  and  hydrogen. 

Kerosene,  as  well  as  the  two  heavier  oils,  headlight 
and  lubricating,  if  properly  graded  are  inexplosive.  All 
the  grades  of  gasoline,  however,  especially  numbers  4 
and  5,  are  so  volatile  that  there  is  constant  danger  of 
their  explosion  when  used  in  the  household  for  any 


HOUSEHOLD    FUELS  67 

purpose.  Because  several  of  the  names  which  were 
formerly  used  for  the  lighter  grades  of  mineral  oils  by 
refiners  and  dealers  have  been  discontinued  by  most 
dealers,  only  the  names  kerosene  and  gasoline  will  now 
be  used  in  this  essay  for  the  mineral  oils  t  which  have  a 
place  among  household  fuels. 

Tests  of  Kerosene.  The  lighter  oils  mix  so  readily 
and  completely  with  kerosene  that  it  is  impossible  to 
detect  the  mixture  by  sight.  The  danger  of  using  such 
a  mixture  made  it  necessary  that  standards  of  grade 
should  be  fixed  by  law  and  municipal  regulations,  which 
has  accordingly  been  done  in  all  civilized  countries. 
Formerly  there  was  a  constant  inducement  to  violate 
those  laws  and  regulations,  because  the  lighter  oils  were 
the  cheaper  and  it  was  easy  for  any  person  to  make  the 
mixture.  There  has  lately  arisen  a  greatly  increased 
demand  for  the  lighter  oils  and  a  consequent  increase 
in  their  price,  until  it  exceeds  that  of  kerosene.  There- 
fore the  chief,  if  not  the  only,  inducement  to  adulterate 
kerosene  has  been  removed. 

The  standard  tests  which  have  been  established  by 
law  are  based  upon  the  specific  gravity  of  the  oil  to  be 
tested,  and  on  what  is  called  its  flashing  point.  Formerly 
a  test  was  used  which  was  called  the  burning  point,  but 
the  flashing  test  is  much  the  more  efficient,  and  is  prac- 
tically the  only  one  now  used.  The  original  way  of 
determining  the  flashing  point  was  to  place  some  of  the 
oil  to  be  tested  in  an  open  cup  and  to  heat  it  slowly. 
A  thermometer  was  placed  in  the  oil  and  the  temperature 
noted  at  which  sufficient  gas  was  given  off  to  cause  a 
slight  explosion  when  a  lighted  match  was  applied. 


68  HOUSEHOLD    FUELS 

Now,  however,  there  are  specially  constructed  instru- 
ments in  use,  called  oil  testers,  by  which  the  flashing 
point  can  more  easily  and  accurately  be  determined. 
The  flashing  test  is  regarded  as  absolutely  essential  by 
all  authoritative  regulations,  the  requirements  of  which 
vary  from  110°  to  200°  F.  In  some  of  the  states 
municipal  regulations  require  the  last  named  flashing 
point,  which  is  the  highest  test  required  in  any  country. 

To  determine  the  specific  gravity  of  kerosene,  an 
instrument  called  a  hydrometer  has  been  used,  and  the 
required  rate  by  that  test  has  varied  from  .807  to  .880. 
Some  municipalities,  however,  consider  this  test  as  of 
little  importance,  and  therefore  do  not  include  it  in  their 
regulations.  Owing  to  these  state  and  municipal  regu- 
lations and  the  removal  of  inducement  to  adulterate 
kerosene,  the  use  of  that  fuel  is  likely  to  be  safe  in  our 
households. 

The  well-known  odor  which  arises  from  gasoline 
and  impure  kerosene  is  usually  due  to  the  vapor  of 
gasoline  only,  but  sometimes  a  sample  of  kerosene  which 
has  stood  the  strictest  tests  of  flashing  point  and  specific 
gravity  will  have  a  strong  odor  somewhat  similar  to  that 
of  gasoline.  In  such  cases  the  odor  is  due  to  the  pres- 
ence in  the  liquid  of  a  small  amount  of  sulphur,  which 
it  has  been  found  very  difficult  to  remove.  Its  presence, 
fortunately,  is  only  unpleasant,  not  dangerous.  Such 
presence  of  sulphur  in  petroleum  is  usually  confined  to 
certain  regions. 

Gasoline.  It  has  already  been  mentioned  that 
dealers  have  begun  to  designate  all  the  mineral  oils 
which  are  lighter  than  kerosene  by  the  one  name,  gaso- 


HOUSEHOLD    FUELS  69 

line,  and  that  numbers  are  now  used  instead  of  the 
former  grade  names.  The  gasolines  are  all  explosive, 
and  some  of  them  highly  so.  Still,  even  the  lightest 
grades  may  be  safely  used  by  a  competent  and  careful 
person;  but  so  many  terrible  accidents  have  happened 
in  connection  with  its  use  that  it  should  not  be  admitted 
to  the  household,  even  for  other  than  fuel  purposes. 
This  judgment  of  the  danger  in  using  gasoline  has 
caused  the  authorities  of  New  York  City  to  forbid  the 
use  of  the  gasoline  stoves  in  any  house,  and  like  regula- 
tions are  becoming  common  in  other  cities.  Insurance 
companies  also  require  that  gasoline  shall  not  be  used 
in  any  house  they  insure. 

The  fact  that  coal  oil  and  petroleum  are  practically 
identical  naturally  suggests  that  petroleum  originated 
from  coal  in  the  earth ;  but  there  are  many  known  facts 
which  are  opposed  to  that  belief.  Although  it  is  true 
that  some  petroleum  has  been  found  in  strata  which 
overlie  and  underlie  beds  of  coal,  yet  no  petroleum  has 
been  found  free  in  any  of  those  coal  beds.  Also  it  is 
certain  that  the  great  oil  fields  of  the  world  have  no 
connection  with  coal  fields.  However,  it  is  the  general 
belief  of  geologists  that  petroleum  has  originated  from 
the  remains  of  plants,  and  perhaps  in  part  from  the 
remains  of  animals,  that  formerly  existed.  Still,  it  is 
proper  to  mention  that  a  noted  Russian  chemist  opposes 
that  view,  and  claims  that  petroleum  is  of.  chemical 
origin  in  the  earth. 

Alcohols.  There  are  several  kinds  of  alcohol  known 
to  chemists,  but  only  two  of  them  are  usable  as  house- 
hold fuels.  These  are  ethyl  alcohol,  commonly  called 


7°  HOUSEHOLD    FUELS 

grain,  or  ninety-five  per  cent,  alcohol,  and  that  which 
is  obtained  from  wood,  or  wood  alcohol.  They  are  both 
limpid,  colorless  liquids,  which  will  ignite  at  the  touch 
of  flame  and  burn  with  a  strong  flame  of  their  own, 
which  gives  much  heat  but  little  light,  and  no  smoke 
or  residue. 

Wood  alcohol  is  much  less  desirable  as  a  household 
fuel  than  ethyl  alcohol,  and  is  much  less  efficient.  The 
number  of  calories  produced  by  the  burning  of  wood 
alcohol  is  only  about  half  of  that  which  the  burning  of 
grain  alcohol  produces.  The  two  alcohols  are  also  very 
different  in  taste,  odor,  and  in  the  effect  upon  one  who 
may  drink  them.  Ethyl  alcohol  is  the  alcohol  of  wines 
and  other  intoxicating  drinks.  Its  odor  is  not  unpleasant 
and  its  taste  is  slightly  biting.  On  the  other  hand, 
methyl  alcohol  has  an  odor  and  taste  so  very  offensive 
that  it  is  undrinkable  except  by  one  whose  taste  has 
long  been  impaired  by  drunkenness,  or  otherwise ;  and 
when  it  is  taken  into  the  stomach  it  is  a  virulent  poison. 

Both  of  the  alcohols  are  composed  of  the  same 
chemical  elements,  carbon,  hydrogen,  and  oxygen,  their 
differences  being  due  to  the  different  proportions  of 
those  elements  in  each,  and  also  to  the  difference  in  the 
manner  of  their  combination.  The  manner  of  origin 
of  these  two  alcohols  is  also  very  different.  So  far  as 
is  now  known,  the  only  method  of  producing  ethyl 
alcohol  is  by  the  fermentation  of  some  form  of  sugar, 
and  its  distillation  from  the  substance  so  fermented. 
The  reason  why  this  alcohol  is  so  often  spoken  of  as 
grain  alcohol  is  that  in  our  country  it  is  largely  dis- 
tilled from  Indian  corn,  or  some  other  grain  the  starch 


HOUSEHOLD    FUELS  71 

of  which  has  been  changed  to  some  form  of  sugar. 
Molasses  obtained  in  the  process  of  the  making  of  cane 
sugar  has  been  much  used  for  the  production  of  ethyl 
alcohol,  and  it  may  be  produced  by  fermenting  any 
substance  which  contains  starch  or  any  kind  of  sugar. 

Methyl  alcohol  is  known  by  several  different  names, 
the  best  known  of  which  is  wood  alcohol ;  but  it  is  often 
called  wood  spirit  and  pyroxylic  spirit.  This  alcohol  is 
not  obtained  by  fermentation,  but  by  a  process  known 
as  the  destructive  distillation  of  wood.  Most  of  the 
methyl  alcohol  sold  in  the  markets  is  obtained  as  one 
of  the  by-products  of  the  wood  which  is  used  in  the 
improved  kilns  for  making  charcoal,  as  was  described 
in  a  preceding  chapter. 

Although  the  alcohols  are  exceedingly  volatile  and 
combustible,  they  do  not,  properly  speaking,  explode, 
as  do  the  lighter  mineral  oils.  They  may,  however, 
cause  serious  damage  if  spilled  on  clothing  near  a  fire, 
because  of  their  ready  combustion.  Still,  they  may 
always  be  burned  safely  by  careful  persons  in  the  well- 
known  small  alcohol  lamps  and  chafing  dishes  and  in 
the  modern  alcohol  stoves.  There  have  recently  come 
into  use  stoves  for  the  burning  of  alcohol  which  are 
large  enough  to  hold  utensils  of  moderate  size.  In  these 
stoves  the  alcohol  is  vaporized  before  it  reaches  the 
burners,  the  effect  of  which  is  to  produce  flames  similar 
to  those  of  the  blue-flame  gas  burner. 

The  extremely  high  tax  which  has  been  for  so  many 
years  placed  on  ethyl  alcohol  by  the  United  States 
government  has  had  the  effect  of  almost  prohibiting  its 
use  as  a  fuel.  The  increasing  demand  for  fuel,  and  the 


72  HOUSEHOLD    FUELS 

fact  that  a  large  number  of  farm  products  which  have 
hitherto  been  thrown  away  may  be  made  to  yield  alcohol, 
has  induced  the  government  to  reduce  greatly  the  tax 
on  alcohol  provided  it  shall  be  "denatured."  The  object 
of  denaturing  alcohol,  that  is,  the  changing  of  it  from 
its  natural  condition,  is  to  render  it  undrinkable  and 
at  the  same  time  not  to  impair  its  value  as  a  fuel  or 
its  usual  use  in  the  industrial  arts.  What  substances 
shall  be  added  to  the  alcohol,  and  in  what  proportions, 
is  prescribed  by  law.  The  substances  must  be  so  offen- 
sive to  the  taste  that  it  will  make  the  mixture  undrinkable. 
The  chief  substance  thus  prescribed  is  wood  alcohol.  In 
addition  there  may  be  oil  of  turpentine,  benzine,  carbolic 
acid,  and  many  other  substances.  A  list  of  these  sub- 
stances is  given  on  page  8  of  Farmer's  Bulletin  268, 
published  by  the  United  States  Department  of 
Agriculture. 


CHAPTER   VIII 
GASEOUS    FUELS 

'"T"*HE  term  gas  is  applied  to  those  substances  which 
-*-  are  invisible  and  impalpable,  and  which  may  be 
composed  of  a  single  chemical  element,  or  a  compound 
of  elements,  or  they  may  be  a  mere  mechanical  mix- 
ture of  other  gases.  They  are  more  or  less  in  a  condition 
similar  to  that  of  air,  which  is  itself  composed  of  gases. 
Some  of  them  are  incombustible,  some- support  combus- 
tion, and  some  are  themselves  combustible.  It  is  only 
the  last  named  class  with  which  we  are  now  concerned. 
It  is  shown  in  the  preceding  chapter  that  all  fuels 
which  burn  only  with  flame  must  be  reduced  to  a  gaseous 
condition  before  ignition,  and  that  the  semi-solid  and 
liquid  fuels  are  in  that  case  really  condensed  gaseous 
fuels.  The  wick  in  use  for  both  of  those  kinds  of  fuel 
not  only  localizes  the  flame,  but  serves  as  a  vehicle  to 
convey  the  fuel  in  its  liquid  state  uniformly  and  in  suit- 
able quantity  to  the  base  of  the  flame.  It  is  here  that 
the  service  of  the  wick  ends,  and  here  that  those  con- 
densed fuels  become  identical  with  the  gaseous  fuels. 
Illuminating  gas  being  already  in  that  reduced  condition 
needs  no  such  preparation,  and  is  burned  from  small 
openings  in  those  familiar  appliances  called  burners, 
through  which  it  is  made  to  pass  by  pressure  within 
the  gas  pipes.  All  the  illuminating  gases  will  ignite 
instantly  at  the  touch  of  flame  or  of  an  electric  spark, 

73 


74  HOUSEHOLD    FUELS 

as  it  issues  from  the  burner,  and  it  is  instantly  extin- 
guished by  shutting  off  the  flow  of  gas.  These  familiar 
facts  are  repeated  here  as  a  basis  for  references  that 
are  to  be  made  in  following  paragraphs. 

It  was  not  until  near  the  close  of  the  eighteenth 
century  that  it  was  demonstrated  that  gas  from  coal 
might  be  used  as  a  fuel  for  lighting,  and  it  was  many 
years  afterward  that  its  use  as  a  heating  fuel  was  recog- 
nized. The  first  illuminating  gas  was  made  from  bitu- 
minous coal,  but  other  gaseous  compounds  and  mixtures 
have  since  been  introduced  which  have  largely  super- 
ceded  coal  gas  in  use  for  both  lighting  and  heating. 
The  artificial  gases  which  are  now  used  as  household 
fuels  are  known  as  coal  gas,  water  gas,  gasoline  gas 
(sometimes  called  air  gas),  and  acetylene  gas,  respec- 
tively. Besides  these,  great  quantities  of  natural  gas 
have  been  discovered  in  some  parts  of  our  country  by 
boring  in  the  earth.  All  these  gases  are  spoken  of  col- 
lectively as  illuminating  gases,  although  they  are  largely 
used  for  heating  purposes  also. 

Pure  coal  gas  is  a  pure  hydrocarbon,  and  therefore 
a  perfect  fuel.  It  is  the  most  efficient  and  unobjection- 
able of  all  the  gaseous  fuels  for  heating  and  lighting. 
It  is  claimed  by  some  gas  experts  that  a  mixture  of  coal 
gas  and  water  gas  may  be  made  which  is  superior  to 
any  coal  gas  alone.  This  assertion  has  apparently  never 
been  proved  to  the  satisfaction  of  consumers.  Coal  gas 
may  be  made  from  any  coal  which  contains  a  large  pro- 
portion of  hydrogen.  The  best  for  this  purpose  is 
unquestionably  bituminous  coal,  because  it  is  rich  in 
hydrogen  and  free,  or  easily  freed,  from  all  deleterious 


HOUSEHOLD    FUELS  75 

substances.  The  best  of  heating  coals,  anthracite,  is 
excluded  in  this  statement  because  of  its  lack  of 
hydrogen. 

A  part  of  the  process  of  making  coal  gas  has  been 
incidentally  described  in  Chapter  IV  as  a  part  of  the 
process  of  coke  making,  but  it  is  repeated  here  to  give  a 
connected  account  of  gas  making.  In  the  process  of 
making  coal  gas,  the  coal  is  placed  in  kind  of  long 
ovens,  called  retorts,  which  have  an  opening  only  at  the 
front  end,  through  which  the  coal  is  filled.  Sometimes 
these  retorts  are  made  of  iron  and  sometimes  of  a 
variety  of  fire-clay,  and  are  set  in  masonry,  with  a  fire- 
place under  each.  A  pipe  is  attached  to  the  upper  side 
of  each  retort  to  lead  off  the  gas  as  it  escapes  from  the 
coal  within.  After  the  coal  is  introduced,  the  front 
opening  of  each  retort  is  tightly  closed  and  sealed.  The 
retorts  are  then  submitted  to  a  high  heat,  which  liberates 
the  gas  and  other  volatile  products  from  the  coal,  all  of 
which  escape  from  the  retorts  by  the  exit  pipes.  The 
gas  is  immediately  passed  through  a  process  of  purifica- 
tion, while  the  by-products,  which  are  more  or  less 
valuable,  are  saved.  The  purified  gas  is  conducted  by 
pipes  to  a  very  large  receptacle,  called  a  gas  holder  or 
gasometer,  which  has  much  the  appearance  of  a  huge 
inverted  cup. 

This  huge  gasometer,  floating,  full  of  gas,  upon  an 
open  cistern  full  of  water,  is  connected  to  pipes  which 
pass  under  ground  to  the  places  where  the  gas  is  con- 
sumed. It  is  the  weight  of  the  floating  gasometer  that 
furnishes  the  force  to  distribute  the  gas  in  the  under- 
ground pipes.  The  gas  made  and  distributed  in  this  way 


76  HOUSEHOLD    FUELS 

consists  of  hydrogen  from  the  coal,  together  with  a  part 
of  its  carbon.  The  residue  left  in  the  retorts  is  coke, 
which  has  already  been  described  under  the  head  of  solid 
fuels. 

Water  Gas.  This  gas  is  so  called  because  a  portion 
of  both  the  hydrogen  and  oxygen  of  which  it  is  com- 
posed is  obtained  by  decomposing  water.  Water,  in 
the  condition  of  superheated  steam,  is  passed  over  a 
mass  of  glowing  anthracite  and  is  decomposed  by  the 
intense  heat  of  the  burning  coal.  The  hydrogen  of 
the  water  is  set  free  and  the  oxygen  of  the  water  unites 
with  carbon  from  the  anthracite,  forming  the  gas,  carbon 
monoxide.  The  freed  hydrogen  and  the  carbon  monox- 
ide together  form  the  mixture  known  as  water  gas. 
This  gas  mixture,  although  combustible,  produces  only 
a  slight  flame.  Burning  hydrogen  gives  little  light 
but  much  heat,  and  the  mixture  of  these  two  gases 
alone  does  not  produce  a  serviceable  gas  either  for 
heating  or  lighting.  Therefore,  to  make  this  mixture 
serviceable  it  is  necessary  to  enrich  it.  The  enrichment 
process  was  originally  accomplished  by  passing  the  mix- 
ture of  hydrogen  and  carbon  monoxide  immediately 
to  a  receiver,  where  more  of  both  hydrogen  and  carbon 
were  added  to  it.  These  additional  elements  were  sup- 
plied by  petroleum,  and  the  mixture  of  water  gas  and 
petroleum  was  subjected  to  great  heat,  which  changed 
the  liquid  petroleum  to  a  gaseous  condition  which  is  so 
firmly  fixed  by  the  process  that  it  cannot  return  to  its 
liquid  condition  on  cooling.  Water  gas  so  enriched 
is  therefore  a  complex  mixture  of  hydrogen,  carbon 
monoxide,  and  petroleum  vapor. 


HOUSEHOLD    FUELS  77 

Recently,  a  process  has  been  devised  by  which  the 
petroleum  is  added  to  the  current  of  superheated  steam 
before  mentioned,  so  that  the  enrichment  is  effected 
over  the  glowing  anthracite  when  the  water  gas  is  made. 
Therefore  it  is  not  necessary  by  this  new  method  to 
pass  the  gas  to  a  receiver,  and  it  is  sent  at  once  to  the 
gas  holder  for  service  to  consumers. 

Even  when  water  gas  has  been  enriched  over  the 
glowing  anthracite,  as  has  just  been  described,  it  is  not 
sufficiently  rich  in  either  carbon  or  hydrogen  to  make  a 
good  gas  for  either  heating  or  illuminating  purposes. 
It  has,  however,  often  been  furnished  by  gas  companies 
to  consumers  without  further  improvement.  Still,  most 
of  the  companies  which  furnish  water  gas  now  not  only 
enrich  it  with  petroleum  while  making  it,  but  they  add 
to  it  a  considerable  proportion  of  good  coal  gas.  This 
latter  addition  greatly  improves  the  quality  of  the  gas, 
which,  it  is  claimed  by  some  experts,  is  then  equal  to 
the  best  coal  gas  in  both  heating  and  lighting  qualities. 
It  should,  however,  be  remembered  that  even  the  best  of 
this  compound  gas  contains  a  large  proportion  of  the 
poisonous  carbon  monoxide. 

Gasoline  Gas.  This  gas  is  always  made  on  a 
smaller  scale  than  that  which  is  furnished  by  gas  com- 
panies, and  is  usually  made  in  private  plants  for  rural 
dwellings  and  institutions  where  large  supplies  from  a 
gas  -company  are  not  available.  It  is  a  mixture  of  the 
vapor  of  gasoline  with  air,  for  which  reason  it  was 
formerly  called  air  gas.  A  large  tank  of  gasoline  is 
buried  in  the  ground,  the  law  in  such  cases  generally 
requiring  that  it  shall  not  be  less  than  thirty  feet  from 


78  HOUSEHOLD    FUELS 

the  buildings,  and  into  this  tank  of  gasoline  air  is  forced 
by  means  of  a  pump,  the  structure  of  which  is  so  simple 
that  a  child  can  operate  it. 

The  air  thus  pumped  into  the  gasoline  forces  from 
it  the  gaseous  vapors  into  which  the  volatile  liquid 
readily  separates,  and  these  vapors  and  the  air  together 
escape  through  pipes  from  the  upper  part  of  the  tank 
to  the  mixing  chamber.  This  mixing  chamber,  or  mixer, 
as  it  is  sometimes  called,  is  nearer  the  buildings  than 
the  tank  is  allowed  to  be,  and  here  the  gas  is  mixed  with 
more  air,  which  is  forced  into  the  mixer  by  the  same 
pump  that  forces  air  into  the  tank  of  gasoline'.  From 
the  mixer,  the  gas  which  has  been  derived  from  the 
gasoline  is  mixed  with  so  much  air  that  it  cannot  return 
to  its  liquid  condition,  is  conducted  by  pipes  into  the 
building,  where  it  is  used  for  both  lighting  and  heating 
purposes.  As  gasoline  gas  is  now  prepared  it  makes 
an  excellent  household  fuel  and  does  not  contain  carbon 
monoxide,  which  is  so  large  a  constituent  of  water  gas. 

Acetylene  Gas.  Besides  the  gases  already  men- 
tioned, there  is  another  artificial  gas,  acetylene,  which, 
like  the  gasoline  gas,  is  produced  only  by  private  plants 
for  country  or  village  homes  and  separate  institutions. 
Many  plants  for  making  this  gas  have  lately  been  in- 
stalled. The  cost  of  the  plant  is  not  very  high,  the 
method  of  producing  the  gas  is  simple,  and  the  gas 
gives  a  brilliant  light  when  burning.  Calcium  carbide, 
from  which  acetylene  gas  is  obtained,  is  now  a  mer- 
chantable article.  Pieces  of  it  are  dropped  automatically 
into  water  which  is  contained  in  a  suitable  receptacle. 
The  gas,  which  is  a  pure  hydrocarbon,  immediately 


HOUSEHOLD    FUELS  79 

results  by  chemical  decomposition  and  is  ready  for  use. 
It  is  conveyed  from  the  generating  apparatus  by  ordi- 
nary gas  pipes  into  the  house,  and  burned  as  is  ordinary 
gas.  This  gas,  however,  requires  specially  constructed 
burners. 

Many  objections  have  been  urged  against  the  use  of 
acetylene  gas  in  the  household,  notwithstanding  the 
excellence  of  its  light.  It  is  certainly  violently  explosive, 
or  may  become  so  if  not  used  with  great  care.  It  has 
the  reputation  of  being  virulently  poisonous  if  inhaled, 
but  manufacturers  of  acetylene  supplies  deny  this.  The 
expense  of  running  an  acetylene  plant  is  greater  than 
is  that  for  any  other  gas  plant,  but  the  plant  itself  is 
not  proportionately  expensive. 

The  housekeeper's  experience  with  acetylene  gas 
may  be  gained  under  varying  conditions.  She  may  be 
delighted  with  the  brilliant  flame  which  this  gas  pro- 
duces as  it  comes  from  the  pure  and  clean  solution  of 
calcium  carbide,  or  she  may  have  a  very  different  experi- 
ence, even  if  the  danger  of  poison  and  explosion  has 
been  overestimated.  That  is,  she  is  likely  to  have  an 
unpleasant  experience  with  acetylene  gas  in  its  crude 
state  w7hen  the  flame  of  the  burner  of  her  range  "flares 
back"  with  a  lurid,  ill-smelling,  and  angry  flame.  That 
flame  is  not  the  flame  of  common  gas  that  the  range 
is  supplied  with,  but  is  the  result  of  a  vitiated  condition 
of  that  gas,  and  consists  of  a  mixture  of  acetylene  and 
carbon  monoxide,  both  of  which  are  formed  at  the  air 
inlet  of  the  burner  by  the  incomplete  combustion  of  the 
gas  in  use.  There  can  be  no  question  of  the  poisonous 
quality  of  the  carbon  monoxide,  and  that  of  the  crude 
acetylene  is  not  less  so. 


8O  HOUSEHOLD    FUELS 

Natural  Gas.  This  gas,  which  is  a  hydrocarbon, 
occurs  naturally  in  the  earth,  and  is  obtained  in  sufficient 
quantity  for  practical  use  by  borings  like  those  which 
are  made  for  mineral  oil  and  artesian  waters.  It  is  a 
valuable  fuel  for  heating  purposes,  but  it  does  not  give 
quite  so  brilliant  a  light  as  does  coal  gas.  It  is  abundant 
in  some  regions,  but  in  the  greater  part  of  our  country 
it  is  not  known  to  exist.  From  some  of  the  well-pipes 
the  gas  rushes  with  great  force,  but  the  force  of  the 
flow  perceptibly  diminishes  in  all  of  them  with  their 
use. 

More  or  less  gas  of  a  similar  kind  escapes  from 
petroleum  as  it  gushes  from  the  wells,  and  such  gas 
sometimes  issues  spontaneously  in  small  quantities  from 
fissures  in  the  rocks,  or  from  the  earth.  It  is  gas  of 
this  kind  that  causes  explosions  in  coal  mines,  and  is 
called  fire-damp  by  the  miners. 

In  those  regions  where  natural  gas  is  obtained  it  is 
used  successfully  for  both  light  and  heat,  not  only  in  the 
industrial  arts,  but  in  the  household.  As  might  have 
been  expected,  there  are  sure  indications  of  a  gradual 
failure  of  the  supply  of  natural  gas,  and  in  many  places 
the  supply  has  already  given  out.  This  failure  has 
occurred,  not  only  in  the  less  important  borings,  but 
in  some  of  those  from  which  the  supply  was  formerly 
abundant.  Geologists  generally  believe  that  the  origin 
of  natural  gas  was  similar  to  that  of  the  mineral  oils, 
that  is,  that  it  has  resulted  from  some  of  the  great 
accumulations  of  vegetable  matter  that  are  known  to 
have  existed;  but  the  actual  proof  of  such  origin  has 
not  yet  been  fully  determined. 


CHAPTER    IX 
ECONOMY    OF    FUELS 

THIS  chapter  is  devoted  mainly  to  remarks  of  a 
supplementary  character  upon  subjects  which  have 
been  discussed  or  referred  to  on  the  preceding  pages, 
besides  others  in  which  the  practical  housekeeper  is 
especially  interested.  None  of  those  subjects  is  of  more 
importance  in  the  economy  of  the  household,  especially 
in  the  rural  districts,  than  is  that  which  pertains  to  the 
liability  to  injury  of  wood  fuels,  and  the  necessity  of 
their  careful  preservation.  If  these  remarks  appear 
to  be  censorious  in  some  respects,  it  is  because  of  the 
prevalent  inexcusable  wastefulness  of  wood  fuel.  That 
wastefulness  is  so  great  as  to  justify  an  estimate  of  a 
loss  of  fifty  per  cent  in  the  possible  heating  power  of 
the  marketed  wood  fuel  of  our  country.  To  these 
remarks  are  added  some  statements  concerning  methods 
of  measurement  of  fuels,  and  cautions  concerning  the 
use  of  some  of  the  others. 

Although  wood  is  so  extensively  used  as  a  household 
fuel,  and  custom  as  to  the  manner  of  its  measurement 
for  sale  is  nominally  uniform  throughout  the  land,  no 
other  kind  of  fuel,  and  perhaps  no  other  kind  of  mer- 
chandise, is  bought  and  sold  with  so  little  regard  to  its 
quantity  and  quality.  A  legal  cord  of  wood  contains 
128  cubic  feet,  and  municipal  regulations  usually  require 
that  the  sticks  shall  be  of  the  full  length  of  four  feet, 

81 


82  HOUSEHOLD    FUELS 

in  addition  to  one-half  of  the  sloping  cut  at  each  end. 
Those  regulations  also  require  that  the  sticks  of  wood 
shall  be  corded  with  as  little  space  between  them  as 
practicable. 

By  some  dealers  these  regulations  are  habitually 
disregarded,  and,  although  many  formally  comply  with 
the  law,  full  legal  measurement  is  often  exceptional.  In 
a  not  unusual  case  of  this  kind  a  quantity  of  wood 
is  sawed  into  very  short  pieces,  put  into  a  cart,  and 
delivered  by  dumping,  with  a  bill  for  half  a  cord.  If 
the  purchaser  should  have  a  fuel  bin  four  feet  long, 
four  feet  high,  and  four  feet  wide,  the  exact  dimensions 
of  half  a  cord,  and  expect  that  load  of  wood  to  fill  it 
if  closely  packed,  it  is  superfluous  to  say  that  he  will  be 
disappointed.  If  the  half  cord  of  \vood  should  be  pur- 
chased as  four- foot  cord  wood,  it  will  not  be  a  hard  task 
to  test  the  measure  with  a  foot  rule  or  a  yard  stick.  It 
will  doubtless  appear  that  the  manner  of  packing  of  the 
purchaser  will  differ  greatly  from  that  of  the  seller. 

But  the  loss  to  which  the  purchaser  of  wood  fuel 
is  subjected  is  far  greater  with  reference  to  quality 
than  to  quantity.  Moreover,  much  of  the  loss  of 
quality  is  occasioned,  not  by  intentional  deception,  but 
by  ignorant  neglect  and  want  of  that  practical  sentiment 
which  bestows  proper  regard  upon  everything  that  has 
borne  the  impress  of  life. 

There  can  be  no  doubt  that  everything  that  man 
has  ever  used  for  fuel  had  its  origin  in  some  form  of 
life.  The  range  of  fuel  origin  in  extinct  forms  extends 
from  anthracite,  on  the  one  hand,  to  natural  gas,  that 
came  from  unknown  vegetation,  on  the  other.  Alan  has 


HOUSEHOLD    FUELS  83 

not  only  been  ready  to  use  the  remains  of  extinct  forms 
of  life  for  fuel,  but  to  destroy  that  of  present  forms.  It 
is  true  that  he  has  innocently  obtained  large  quantities 
of  fats  and  oils  from  vegetable  fruits  and  nuts,  but 
when  he  has  wanted  animal  oils  and  fats  he  has  sent 
out  thousands  of  his  fellowmen  for  the  slaughter  of  the 
whale  and  seal,  and  their  victims  have  numbered  millions. 

After  making  such  havoc  with  animal  life  it  is  not 
to  be  expected  that  he  should  show  any  regard  for  a 
tree.  If  he  wants  firewood,  he  kills  a  tree  to  obtain  it. 
He  does  not  then  give  it  the  care  which  a  butcher  gives 
to  the  body  of  an  animal  which  he  kills,  but  ruthlessly 
cuts  its  graceful  trunk  in  pieces  and  scatters  them  upon 
the  ground,  where  they  are  left  to  decay  and  to  the 
ravages  of  burrowing  grubs.  If  he  is  a  dweller  where 
trees  are  plentiful,  and  desires  to  cultivate  the  ground 
upon  which  they  grow,  he  girdles  them.  That  is,  he 
kills  them  by  cutting  a  continuous  wound  around  the 
trunks  with  his  ax.  The  trees  slowly  die,  and  at  his 
leisure  he  cuts  them  up  and  brings  the  damaged,  worm- 
eaten  wood  to  the  fuel  markets.  The  full  extent  and 
character  of  such  damage  to  firewood  can  be  properly 
appreciated  only  by  examination  of  the  structure  and 
manner  of  growth  of  trees. 

The  growing  tree  constantly  produces  fresh  organic 
substance  within  its  tissues,  and  it  is  this  substance  in 
the  wood  that  is  peculiarly  subject  to  decay.  The  part 
of  wood  which  becomes  charcoal,  or  nearly  pure  carbon, 
is  not  subject  to  organic  decay  when  separated  by  heat 
from  the  organic  substances  referred  to.  That  fresh 
organic  substance  consists  of  the  protoplasmic  contents 


84  HOUSEHOLD    FUELS 

of  the  living  cells,  the  delicate  walls  of  which  become 
wood  by  hardening,  thickening,  and  elongation.  The 
growing  cells  receive  the  necessary  moisture  from  the 
food-sap  which  the  tree  absorbs  from  the  earth  by  its 
roots.  That  moisture  is  constantly  present  in  the  grow- 
ing tree,  and  remains  after  it  is  dead  as  an  aid  to 
decomposition  of  the  delicate  cells.  The  only  practicable 
way  to  prevent  that  decay  in  wood  without  impairing 
its  fuel  value  is  by  thoroughly  drying  it  as  soon  as 
possible  after  the  trees  are  felled,  and  keeping  it  dry 
until  it  is  to  be  burned. 

As  one  examines  the  woody  structure  of  the  square- 
cut  end  of  the  woodman's  log,  especially  after  it  has 
lain  a  few  weeks  upon  the  ground,  it  is  evident  that 
some  portions  are  liable  to  decay  sooner  than  others. 
The  inner  portion  of  the  log,  comprising  the  greater  part 
of  its  bulk,  and  commonly  called  the  heartwood,  is 
denser  and  darker  in  color  than  is  the  narrower  portion, 
having  a  similar  woody  texture,  which  lies  immediately 
outside  of  it.  That  outer  layer  is  commonly  called  sap- 
wood,  but  botanists  call  it  alburnum.  The  contrast  in 
color  between  the  heartwood  and  sapwood  is  very  great 
in  some  trees.  In  the  juniper,  or,  as  it  is  commonly 
called,  red  cedar,  the  heartwood  is  red  and  the  sapwood 
is  white.  In  the  black  walnut  the  heartwood  is  brown 
and  the  sapwood  nearly  white.  But  the  difference 
between  the  heartwood  and  sapwood  in  which  we  are 
now  specially  concerned  is  shown  by  the  greater  liability 
of  the  latter  to  decay. 

There  is  between  the  sapwood  and  the  bark  a  very 
thin  layer  of  cells  which  is  called  the  cambium  layer, 


HOUSEHOLD    FUELS  85 

and  which  is  still  more  subject  to  decay  than  is  the  sap 
wood.  In  the  living  tree  these  cells  are  minute  spherical 
or  polygonal,  living,  and  constantly  increasing  vegetable 
cells.  When  first  formed  they  are  extremely  delicate, 
but  their  so-called  cell  walls  soon  elongate,  thicken,  and 
take  on  a  woody  texture.  They  therefore  become  wood 
cells  on  the  inner,  and  bark  cells  on  the  outer  side  of  the 
cambium  layer,  their  former  places  in  the  cambium  layer 
being  constantly  filled  by  new  cells  as  long  as  the  tree 
increases  in  growth.  When  the  tree  is  cut  down  it  is 
killed,  and  no  more  cells  form  in  any  part  of  it.  Unless 
the  wood  is  then  very  thoroughly  dried,  the  protoplasm 
which  its  cells  contain  begins  at  once  to  decay,  and  the 
decay  of  the  protoplasm  soon  involves  the  woody  tissue, 
especially  that  of  the  sap  wood  and  the  delicate  cells  of 
the  cambium  layer.  The  latter  cells  are  the  first  to  yield. 
The  outer  bark  and  heartwood  resist  decay  longest 
because  there  is  very  little  protoplasm  left  in  their 
thickened  and  hardened  cells. 

When  the  wood  of  newly  felled  trees  is  left  exposed 
to  the  weather  or  stored  in  a  damp  place,  the  effect  of 
the  decay  is  first  noticeable  by  the  loosening  and  cleav- 
ing off  of  the  bark.  This  is  because  the  new  cells 
forming  the  cambium  layer  have  completely  decayed, 
and  nothing  remains  to  hold  the  bark  from  falling  away 
from  the  wood.  This  is  the  first  stage  of  firewood  decay* 
which  is  practically  identical  with  the  decay  of  all  fresh 
vegetable  substances.  Cut  into  the  sapwood  of  a  stick 
from  which  the  bark  has  been  thus  loosened  and  it  will 
be  seen  to  have  a  discolored  appearance,  and  a  little 
later  its  rotten  condition  will  be  unmistakable.  This  is 
the  second  stage  of  decay. 


86  HOUSEHOLD    FUELS 

Often  not  only  logs  and  sticks  in  which  decay  has 
plainly  begun,  but  others  which  are  apparently  sound 
may  be  found  to  be  completely  riddled  by  boring  insect 
grubs  which  have  developed  from  eggs  that  were  de- 
posited on  the  outer  surface  of  the  bark  after  the  tree 
was  felled.  Immediately  upon  being  hatched  all  wood 
grubs  burrow  into  the  wood  in  search  of  remains  of  the 
protoplasmic  contents  of  the  wood  cells,  which  furnish 
their  necessary  food.  They  have  a  short,  worm-like  body 
and  a  large  head  armed  with  strong,  horny  jaws.  With 
those  jaws  the  grub  tears  up  the  wood  to  a  condition 
resembling  fine  sawdust,  and  swallows  every  particle  of 
it.  The  proteid  nutriment  is  absorbed  by  the  intestinal 
canal  from  the  sawdust-like  material  as  it  passes  through. 
The  refuse  material  is  continuously  evacuated  and  packed 
so  firmly  in  the  burrow  behind  the  grub,  as  it  goes  for-' 
ward,  that  the  packed  material  closely  resembles  the 
adjacent  decaying  wood. 

The  foregoing  statements  of  the  effects  of  proto- 
plasmic decay  of  wood  fuel  and  of  the  habits  of  boring 
grubs  in  partially  decayed  wood  have  been  selected  as 
practical  illustrations  of  the  great  necessity  of  carefully 
drying  and  housing  the  wood  immediately  after  the  trees 
are  felled.  Extreme  dryness  is  the  best  possible  safe- 
guard against  most  forms  of  rot  and  against  some  of 
the  insect  depredations,  but  unfortunately  every  case 
of  the  latter  kind  cannot  be  met  so  simply. 

For  example,  the  hickory  borer  will  attack  the  wood 
of  that  tree  only  after  the  tree  is  killed,  and  it  is  so  per- 
sistent in  its  attacks  then  that  it  will  sometimes  follow 
that  wood  into  the  woodhouse,  refusing  all  other  kinds. 


HOUSEHOLD    FUELS  8/ 

The  grub  of  that  insect  hatches  out  in  the  spring,  and 
therefore  if  the  hickory  trees  are  felled  in  late  autumn 
or  early  winter  the  wood  will  probably  have  dried  suffi- 
ciently to  resist  the  attacks  of  the  grubs  when  they 
appear.  The  mature  insect  is  one  of  the  long-horned 
(longicorn)  beetles,  and  should  be  killed  at  sight.  It  is 
desirable  to  know  the  habits  of  other  insects  in  their 
relation  to  wood  fuel,  but  only  the  foregoing  statement 
is  selected,  because  hickory  is  the  best  firewood  that  our 
country  affords,  and  the  hickory  borer  is  one  of  the  most 
persistent  of  its  kind. 

It  should  not  be  forgotten  that  the  drying  out  of  the 
original  sap  of  wood  fuel  before  it  is  used  is  absolutely 
essential,  for  wood  is  not  suitable  for  fuel  until  that 
original  moisture  has  been  removed.  The  drying  out 
of  the  sap  and  all  accessory  moisture  is  not  only  essen- 
tial in  preserving  the  wood  from  rot,  but  in  preserving 
its  heating  power.  Water  in  the  fuel  always  changes 
to  superheated  steam  in  the  fire,  and  carries  off  and 
wastes  a  large  proportion  of  the  heat  which  the  fuel 
generates. 

Measurement  of  Fuels.  All  mineral  coal  is  sold 
by  weight,  the  unit  being  the  ton.  Municipal  regulation 
in  certain  parts  of  our  country  requires  2,240  pounds  to 
the  ton,  but  in  many  parts  of  it  only  2,000  pounds  to  the 
ton  are  required.  They  are  called  the  long  ton  and 
the  short  ton,  respectively.  The  relation  of  each  of  these 
tons  to  measured  space  in  fuel  bins  may  be  readily 
learned,  and  such  bins  should  be  well  protected,  even 
for  mineral  coal. 

Wood  is  sold  by  the  cord,  of  128  cubic  feet.     By  the 


88 


HOUSEHOLD    FUELS 


shortening  of  the  length  of  the  sticks  and  loosely  pack- 
ing them  a  difference  of  fifteen  or  twenty  per  cent  may 
be  made  in  favor  of  the  seller. 

Charcoal  and  coke  are  sold  by  the  bushel.  Although 
both  of  these  fuels  are  hardly  subject  to  decay,  they 
absorb  moisture  so  readily  that  they  need  special  care 
in  housing. 

All  the  semi-solid  fuels  are  sold  by  the  pound.  They 
are  comparatively  so  exempt  from  liability  to  decay  that 
only  ordinary  care  is  needed  to  preserve  them. 

The  liquid  fuels  are  sold  by  measure,  the  unit  being 
the  Winchester,  or  wine,  gallon,  containing  231  cubic 
inches.  As  the  cans  in  which  dealers  serve  the  mineral 
oils  to  purchasers  are  rectangular  in  shape,  it  is  easy 
to  estimate  their  capacity. 

The  gaseous  fuels  are  served  to  consumers  by  the 
companies  measured  by  a  meter,  the  unit  being  1,000 
cubic  feet.  The  meter  is  locked  and  controlled  by  the 
company,  but  three  small  dials  on  the  face  of  the  meter 
are  Visible  to  every  one.  These  dials  are  used  by  the 
company  in  rendering  their  bills  for  gas  to  consumers, 
as  indicating  the  amount  of  gas  consumed. 

In  the  purchase  of  the  solid  and  semi-solid  fuels 
there  is  opportunity  for  the  housekeeper  to  use  her 
judgment  as  to  quality  and  quantity  of  the  articles  she 
purchases.  In  the  case  of  the  liquid  fuels,  however, 
she  cannot  so  easily  detect  the  adulterations  and  dilutions 
which  have  been  practiced.  Fortunately,  dilutions  of 
kerosene  are  not  now  to  be  feared,  but  those  of  the 
alcohols  may  occur  in  any  degree  that  a  dishonest  dealer 
may  venture  to  practice.  In  the  case  of  gas  from  the 


HOUSEHOLD    FUELS  89 

public  plant,  she  must,  as  a  rule,  abide  by  the  custom 
of  the  company  as  to  the  quality,  quantity,  and  pressure 
of  service. 

Injurious  Fuels.  The  fact  that  serious  injury  to 
persons  and  property  may  occur  from  contact  with  fire 
is  too  well  known  to  need  mention  except  in  connection 
with  cases  of  special  liability  to  injury  from  the  use  of 
certain  fuels.  There  are  three  different  sources  of  danger 
besides  that  of  common  fire  to  which  the  household 
is  exposed  in  the  use  of  its  fuel,  namely,  that  of  suffo- 
cation, poison  by  inhalation,  and  explosion. 

All  the  kinds  of  gas  which  are  used  for  lighting  or 
heating  are  liable  to  explode,  often  with  great  violence, 
upon  escaping  from  the  pipes  and  mingling  with  the  air. 
All  kinds  of  those  gases  will  produce  suffocation  to  the 
person  breathing  them  in  considerable  quantity,  and  at 
least  a  part  of  them  will  also  act  as  a  virulent  and  some- 
times fatal  poison  when  taken  into  the  lungs.  Fortu- 
nately, poisoning  by  ordinary  contact  with  any  household 
fuel  is  not  to  be  feared,  and  with  the  exception  of  w^Dod 
alcohol  no  fuel  substance  has  the  reputation  of  being 
poisonous  in  the  stomach.  One  will  readily  see  that  both 
the  wood  and  ethyl  alcohol  ought  to  be  kept  beyond  the 
reach  of  those  who  may  possibly  misuse  them. 

Safety  to  the  household  requires  constant  watchful- 
ness against  gas  leakage  of  all  kinds,  especially  as  regards 
its  explosive  qualities.  Leakage  is  best  detected  by  the 
odor  of  the  gas,  which  is  usually  strong  and  unmistak- 
able. Upon  perceiving  the  odor,  the  room  or  suspected 
place  must  at  once  be  fully  ventilated  by  opening  the 
doors  and  windows.  On  no  account  must  a  lighted 


9O  HOUSEHOLD    FUELS 

match  or  other  fire  be  admitted  until  the  ventilation  is 
complete.  The  leak  may  then  be  sought  by  the  sense 
of  smell,  and  if  the  odor  is  strong  the  escape  must  be 
stopped  at  once  by  turning  the  stopcock  of  the  house 
supply  pipe,  which  is  to  be  found  at  one  side  of  the 
meter.  If  the  odor  is  slight,  the  leak  may  be  sought  by 
holding  a  lighted  match  to  the  suspected  place  of  issue. 
If  the  leak  should  be  there,  a  jet  of  flame  will  issue  of  a 
size  comparable  with  the  aperture.  No  leak,  however 
small,  must  be  neglected.  Danger  always  lurks  with 
escaping  gas,  and  safety  lies  in  complete  repair. 

The  flare-back  flame  which  so  often  results  from  the 
lighting  by  a  match  of  the  blue-flame  gas  burners, 
whether  used  for  lighting,  heating,  or  cooking,  should 
be  immediately  stopped  by  turning  off  the  gas  and  re- 
lighting it  as  often  as  is  necessary  to  obtain  a  pure  flame. 
Because  this  flame  consists  of  a  mixture  of  carbon 
monoxide  and  crude  acetylene  gas,  the  necessity  of 
cutting  off  its  flow  is  quite  apparent. 

The  Fireless  Cooker.  An  effective  method  of 
cooking  certain  kinds  of  food  is  by  simmering  for  a 
long  time  over  a  fire  S3  small  as  to  keep  the  food  at 
a  temperature  just  below  the  boiling  point  of  water. 
A  method  of  similar  cooking  may  be  conveniently  accom- 
plished by  a  device  which  is  popularly  known  as  "the 
fireless  cooker,"  which  is  mentioned  here  because  of  its 
present  increasing  popularity  and  usefulness.  It  also 
serves  as  an  illustration  of  the  fact  that  a  very  large 
proportion  of  the  heat  which  is  produced  in  all  of  our 
ordinary  methods  of  cooking  is  utterly  wasted.  The 
present  rate  of  diminution  of  the  world's  supply  of  fuel 
makes  this  subject  one  of  increasing  importance. 


HOUSEHOLD    FUELS  9 1 

This  device  is  cylindrical  or  rectangular  in  shape, 
and  may  differ  much  in  details  of  construction.  The 
most  effective  kind  consists  of  a  double  box  of  either 
wood  or  metal,  the  larger  part  including  the  smaller, 
so  that  there  shall  be  a  considerable  space  between  them, 
to  be  filled  with  asbestos  fiber,  or  some  other  non- 
conductor of  heat.  Still,  the  box  is  often  made  without 
the  interspace,  but  of  material  which  is  known  to 
resist  the  escape  of  heat.  Usually  the  top  or  one  side 
of  the  box  is  removable  or  hinged  as  a  door,  and  the 
joint  between  it  and  the  box  is  secured  by  some  non- 
conducting material.  Whatever  may  be  the  modifica- 
tions of  structure,  it  is  imperative  that  provision  shall 
be  made  for  the  retention  of  heat  within  the  box. 

The  smaller  cookers  hold  only  one  or  two  vessels 
of  food,  but  the  larger  kind  may  be  as  large  as  a  small 
traveling  trunk  and  may  hold  several  food  vessels, 
packed  upon  one  another  if  necessary,  for  which  reason 
the  covers  should  be  flat.  To  increase  the  heat  within 
the  box,  heated  plates  of  cast  iron  may  be  used  to  over- 
lay the  covers.  The  food,  each  kind  in  a  separate  vessel, 
is  heated  to  boiling  over  a  common  fire,  where  the  cast 
iron  plates  are  also  heated,  and  all  are  placed  in  the  box, 
previously  warmed  before  the  fire.  The  closed  box  is 
then  put  in  a  protected  place  for  several  hours,  when 
the  food  will  have  become  thoroughly  cooked  and  remain 
still  hot. 

The  cooking  of  the  food  by  this  method  is  effected 
wholly  by  the  preliminary  heating  that  is  given  it  over 
the  fire,  that  heat  being  retained  in  action  upon  the  food, 
and  its  escape  prevented,  by  the  non-conducting  material. 


92  HOUSEHOLD   FUELS 

While  these  cookers  are  a  valuable  addition  to  domestic 
needs,  it  is  true  that  they  are  adapted  to  only  a  part  of 
the  requirements  of  the  household  for  food  variety. 
Still,  an  ingenious  housekeeper  may  readily  adapt  one 
of  these  cookers  to  the  preparation  of  a  good  variety  and 
generous  quantities  of  nourishing  and  acceptable  food, 
with  an  important  reduction  of  her  own  labor  and  of 
expense  for  fuel. 


CHAPTER   X 
ELECTRICITY 

A  LTHOUGH  the  object  of  this  essay  is  only  to 
•*•  *•  discuss  fuel  substances,  so  much  advance  has 
been  made  in  the  substitution  of  electricity  for  house- 
hold fuels  that  brief  mention  of  it  is  here  appropriate. 
All  recent  text-books  of  physics  describe  what  is  now 
known  of  the  character  and  action  of  electricity,  and  the 
literature  of  that  subject  is  abundant.  It  is  sufficient, 
therefore,  to  say  here  that  electricity  is  not  a  substance, 
but  a  force,  or  a  form  of  energy,  that  under  certain 
conditions  flows  as  a  permeating,  instantaneous  current 
in  certain  directions  through  various  substances,  but  not 
through  others.  The  former  are  called  conductors  and 
the  latter  non-conductors  of  electricity.  The  current 
flows  with  much  greater  force  through  some  conductors, 
copper  and  iron,  for  example,  than  through  others. 
Glass  and  India  rubber  are  among  the  most  complete 
non-conductors.  Many  substances,  among  which  are 
carbon  and  various  metals,  are  tardy  conductors  of  elec- 
tricity, and  when  inserted  by  attachment  between  the 
severed  ends  of  a  good  conducting  wire  they  resist  the 
current.  It  is  this  resistance  that  causes  the  heat  or 
incandescence,  or  both,  in  the  resisting  material.  This 
heat  is  sufficiently  intense  for  all  household  purposes, 
and  the  incandescence  gives  a  light  of  great  and  agree- 
able brilliancy. 

93 


94  HOUSEHOLD    FUELS 

Materials  of  different  degrees  of  conductivity  and 
resistance  are  used  in  the  construction  of  electric  light- 
ing, heating,  and  cooking  appliances,  a  large  variety  of 
which  are  now  offered  for  sale  as  ordinary  merchandise 
in  all  of  our  principal  cities.  The  electric  light  bulb, 
with  its  long  folded  carbon  filament,  has  become  a 
familiar  object,  but  the  use  of  the  heating  and  cooking 
appliances  does  not  expose  them  so  much  to  public 
observation.  The  heating  devices  take  various  forms  of 
radiators,  and  those  which  are  constructed  for  cooking 
are  similar  in  general  form  and  practical  use  to  those 
in  which  the  gaseous  fuels  are  burned,  but  of  course 
the  details  of  their  construction  are  very  different. 

The  advantages  of  the  household  use  of  electricity 
are  its  capacity  for  producing  abundant  light  and  heat 
and  its  entire  cleanliness  and  freedom  from  objection- 
able odors.  There  is  no  escape  of  gases  or  of  products 
of  combustion  into  the  air  of  the  room  in  which  it  is 
used,  as  is  always  the  case  to  a  greater  or  less  extent 
when  liquid  or  gaseous  fuels  are  burned.  The  disadvan- 
tages of  its  domestic  use  are  its  present  greater  cost 
than  that  of  fuels,  and  the  necessity  of  establishing  a 
comparatively  large  plant  to  insure  a  sufficiently  large 
and  constant  supply  of  light  and  heat.  Electricity  is 
therefore  not  at  present  practically  available  as  a  full 
substitute  for  fuels  except  in  cities  and  the  larger  vil- 
lages, or  near  waterfalls  or  other  natural  sources  of 
mechanical  power.  Recourse  to  such  sources  of  power 
is  necessary  because  all  the  electricity  which  has  been 
brought  under  human  control  is  produced  by  its  artificial 
transformation  from  other  forms  of  energy.  Indeed, 


HOUSEHOLD    FUELS  95 

most  of  the  electricity  which  is  now  in  use  is  generated 
by  power  which  has  been  produced  by  the  burning  of 
fuels. 


INDEX 


Acetylene  Gas,  78 

Air  Gas,  77 

Alcohol,  Grain  (Ethyl),  70 

Wood  (Methyl),  48,  70 
Angiosperms,  41 
Anthracite,  30 
Ashes,  Wood,  12 

Bituminous  Coal,  31 
Brimstone  Match,  17 

Camphene,  64 
Candle  Flame,  20 

Making,  54 

Tallow,  53 
Cannel  Coal,  34 
Carbon,  7,  9 
Charcoal,  47 

Kilns,  48 
Chemical  Elements,  5 

Reaction,  6 

Classification  of  Fuels,  2 
Coal,  Bituminous,  31 

Gas,  74 

Non-Bituminous,  34 

Oil,  65,  69 

Semi-Bituminous,  33 
Coke,  32 
Combustion  of  Fuels,  10 

Products  of,  1 1 
Conifers,  45 

Electiicity,  93 
Elements,  Chemical,  5 
Fuel,  6 

Accessory,  8 

Fats,  52 

Fireless  Cooker,  90 

Flame,  Candle,  20 

Combustion,  20 

Flare-Back,  90 

Gas,  23 

Lamp,  23 


Flint,  1 6 

Fuel  Elements,  6 

Accessory,  8 
Fuels,  Classification  of,  2 

Composition  of,  5 

Economy  of,  81 

Gaseous,  73 

Injurious,  89 

Liquid,  60 

Measurement  of,  87 

Semi-Solid,  51 

Solid,  26 

Wood,  37 

Gas,  Acetylene,  78 

Air,  77 

Coal,  74 

Flame  of,  23 

Gasoline,  77 

Natural,  80 

Water,  76 
Gaseous  Fuels,  73 
Gasoline,  68 

Gas,  77 

Grain  Alcohol,  70 
Grubs,  Hickory,  86 

Wood-Boring,  86 

Hydrogen,  8,  9 

Ignition,  14 
Incandescent  Light,  25 
Injurious  Fuels,  89 

Kerosene,  66 
Tests  of,  67 
Kindling,  15 

Lard  Lamps,  53 

Oil,  62 
Lignite,  35 
Liquid  Fuels,  60 

Mantle  Light,  25 


96 


HOUSEHOLD    FUELS 


97 


Matches,  Brimstone,  17 
•  Friction,  18 

Safety,  19 

Measurement  of  Fuels,  87 
Mineral  Fuels,  27 

Oils,  Grades  of,  65 

Natural  Gas,  80 
Nitrogen,  8 

Oil,  Coal,  65,  69 

Lard,  62 

Olive,  6 1 

Palm,  61 

of  Turpentine,  64 

Whale,  62 
Oxidation,  10 
Oxygen,  10 

Palmitin,  57 
Paraffin,  58,  65 
Peat,  26,  35 
Petroleum,  65,  69 


Resin,  50,  58 


Safety  Matches,  19 
Semi-Solid  Fuels,  51 
Solid  Fuels,  26 
Spermaceti,  57 
Stearin,  57 
Sun  Glass,  16 

Tallow  Candles,  53 
Tar  Kiln,  50 
Tinder,  17 

Unusual  Fuels,  46 
Vaseline,  65 

Water  Gas,  76 

Wax,  55 

Wood  Alcohol,  48,  70 

Ashes,  12 

Fuels,  37 

Grubs,  86 

Kinds  of,  42 

Rotting  of,  85 

Structure  of,  84 


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•?. 


!A 


MAR    21980 


BEG.  Gift.    FEB  2 


1980- 


LD  21-100m-2,'55 
(B139s22)476 


General  Library 

University  of  California 

Berkeley 


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190898 


UNIVER? 


.BRARY 


